- Quantum Leap a.k.a. Quantum Leap: Genesis
13 September 1956: Dr. Sam Beckett is the head of a time-travel experiment that one day succeeds in working almost. From the Project Quantum Leap facility in a New Mexico cavern, Sam wakes to find himself in a strange bed, with a strange wife and with an unfamiliar face staring back at him from the mirror. It's 1956, and Sam finds he has somehow "leapt" into the persona of Tom Stratton, test pilot. With no idea how to fly, and with an understandable feeling that the truth would not be believed, he's further handicapped by a "Swiss cheese" memory of his past and he's being observed by some strange, shadowy man.
15 June 1972: Sam materializes as an English professor struggling to resist an over-amorous student, and attempts to reunite his own future girlfriend (Teri Hatcher) with her estranged father at the Watergate Hotel on a momentous night.
- The Right of God
24 October 1974: Sam bounces into the persona of a boxer and straight into a punch. As Clarence "Kid" Cody, he finds he has to fight another day to help two nuns build a chapel and defeat a group of mobsters.
- How the Tess Was Won
5 August 1956: Sam lands in the middle of Texas as a mild-mannered veterinarian and thinks his task is to out-cowboy the headstrong daughter of a rancher. Meanwhile, a young man called Buddy is about to strum a familiar tune that needs the right girl's name for a title....
- Double Identity
8 November 1965: Quantum leaping doesn't seem so bad when Sam wakes in an attic to hear he's a terrific lover but his enthusiasm wanes when he learns he's a Mafia hit man whose rival in love is a very jealous godfather.
- The Color of Truth
8 August 1955: Materializing as an old African-American man in a small Alabama town, Sam finds himself driving Miz Melny and becoming a force in the birth of the Civil Rights movement.
- Camikazi Kid
6 June 1961: Sam is an acne-riddled 17-year-old who loves junk food and cars. He jokes that he's here to clear up his complexion, but he really needs to worry about an older sister who's about to enter a bad marriage.
- Play It Again, Seymour
14 April 1953: Sam leaps into a Humphrey Bogart-lookalike with a dead partner and cops breathing down his neck. Then there's that young Bogey fan who looks a lot like Woody Allen....
- Honeymoon Express
27 April 1960: In order to convince a Senate committee to renew funding for the Quantum Leap project, Al needs Sam to prove his existence in the past by altering an historical event. Meanwhile Sam is a newlywed whose bride's homicidal ex-husband wants to kill him.
- Disco Inferno
1 April 1976: White polyester suits, platform heels, star signs, people getting' down it's Hollywood in the '70s, and Sam finds himself living the perilous life of a disaster-movie stuntman who must prevent a family tragedy.
- The Americanization of Machiko a.k.a. Machiko McKenzie
4 August 1953: Sam goes back to small-town America as a Navy man returning home with a surprise a Japanese wife. But now he must make his family and the townspeople accept her.
- What Price Gloria?
16 October 1961: For the first time, Sam becomes a woman beautiful secretary Samantha and experiences sexual harassment as he helps save his roommate, Gloria, from committing suicide after being jilted by a two-timing lying married man.
- Blind Faith
6 February 1964: As the Beatles prepare to take America by storm, Sam finds himself a brilliant, blind concert pianist who must save a young woman from both her possessive mother and a killer stalking Central Park.
- Good Morning, Peoria
9 September 1959: Sam leaps into the body of disc jockey Howlin' Chick Howell and helps a young woman save her radio station from a small-town's anti-rock'n'roll campaign. He also teaches a portly African-American singer a new dance called the Twist.
- Thou Shalt Not...
2 February 1974: Sam assumes the identity of a rabbi trying to prevent the breakup of a family unable to resolve their anger and guilt over the death of their son. He also helps out a choking man named Dr. Heimlich.
14 October 1964: Sam's eyes are opened to the prejudice facing the mentally challenged when he leaps into the life of Down's Syndrome sufferer Jimmy La Matta.
- So Help Me God
29 July 1957: Sam becomes a lawyer in a bigoted Louisiana town, defending a young African-American woman accused of murdering an influential civic leader's son.
- Catch A Falling Star
21 May 1979: Sam finds himself an understudy in an off-Broadway production of Man of La Mancha who must save the hard-drinking star from falling down drunk on stage and ruining his life.
- A Portrait for Troian
7 February 1971: Sam leaps into the world of the paranormal when he must save a young woman from being driven insane by her dead husband's spirit.
- Animal Frat
19 October 1967: Sam becomes the craziest fraternity brother on campus, who must put aside beer and women to prevent a fellow student from making a fatal mistake by blowing up the chemistry lab.
- Another Mother
30 September 1981: Sam leaps into a newly divorced mother of three and discovers the difficulties of coping with an adolescent son fated to run away from home and then vanish off the face of the Earth as well as a four-year-old who can see Sam as he really is, and Al's hologram, too.
- All Americans
6 November 1962: Sam's a star high-school quarterback whose goal is to stop his best friend and teammate from throwing a vital championship football game.
- Her Charm
26 September 1973: Sam leaps into a hail of bullets as he becomes an FBI agent assigned to protect an abrasive young woman from a murderous mobster.
22 November 1970: Sam finds himself a Native American who has helped his grandfather escape from a nursing home, and must now find a way to help the old man to die with dignity.
- Good Night, Dear Heart
9 November 1957: Sam becomes a mortician obsessed with the apparent suicide of a beautiful German girl.
- Pool Hall Blues
4 September 1954: Sam leaps into the body of Charlie "Black Magic" Walters, a pool player who is about to be challenged by an unscrupulous young pretender with a young woman's future at stake.
- Leaping in Without a Net
18 November 1958: Sam becomes a trapeze artist who must prevent his sister from suffering a fatal fall in a death-defying stunt. But first Sam must conquer his own fear of heights.
- Maybe Baby
11 March 1963: Sam leaps into the formidable body of a nightclub bouncer who is helping a stripper to kidnap a baby girl.
- Sea Bride
3 June 1954: Arriving on the Queen Mary, Sam finds he's a debonair adventurer who must try to prevent his ex-wife from going through with a disastrous remarriage.
1 April 1969: Sam becomes an undercover detective and thinks he must be an April fool when Al tells him his task is merely to prevent a young woman, who believes her husband died in Vietnam, from falling for another man. What he doesn't know is the woman is Al's wife, Beth.
- The Leap Home, Part I
25 November 1969: Sam leaps into his own body at age 16, back in Elk Ridge, Indiana, and gets a chance to alter his family's destiny. His father is heading toward a fatal heart attack, sister Katey is to ruin her future by eloping with an abusive alcoholic, and Tom, the elder brother Sam never really got to know, has enlisted for Vietnam, where he is fated to die.
- The Leap Home, Part II - Vietnam
7 April 1970: Sam finds himself part of an elite marine squad headed by his brother Tom. Knowing his brother died on 8 April, Sam can't believe his mission is actually to save the life of beautiful photojournalist Maggie Dawson. He succeeds in saving Tom but at horrific cost to two other people, including Al.
- Leap of Faith
19 August 1963: Sam leaps into the body of a priest and must prevent the death of a fellow priest who witnessed the murder of a 12-year-old boy. One young boxer that Father Mac coaches calls himself Sly and says "Yo" a lot.
- One Strobe over the Line
15 June 1965: Sam becomes a fashion photographer who has to baby-sit a glamorous model (Monaghan) to prevent her from overdosing on pills and alcohol.
- The Boogieman
31 October 1964: Things go bump in the night as Sam becomes a second-rate horror novelist who witnesses a series of bizarre murders that lead him into a deadly dance with the Devil, who wants to put an end to Sam's "meddling." This spooky tale also sees Sam give his horrific ideas to an aspiring young storyteller named Stephen....
- Miss Deep South
7 June 1958: Sam becomes a contestant in the Miss Deep South beauty pageant with the double task of ensuring he wins third prize while keeping a beautiful fellow contestant (McAdam) from destroying her life in the aftermath of posing for nude photos.
- Black On White On Fire
11 August 1965: On the eve of the Watts riots, Sam has become a promising African-American medical student involved with the white daughter of a police captain. With mayhem on the streets, Sam has to fight to keep the lovers together in an environment of racial hatred that threatens both their lives.
- The Great Spontini
9 May 1974: Oakland, California. Sam is Harry Spontini, a struggling magician whose 12-year-old daughter and assistant (Woodland) dreams of settling down with him. When her estranged mother (Steel) walks back into their lives, Harry faces a custody battle.
- Rebel Without a Clue
1 September 1958: Sam leaps into the body of Shane "Funny Bone" Thomas, a member of a rebellious motorcycle gang, to stop the senseless death of a free-spirited girl (Josie Bissett) obsessed with experiencing the lifestyle of Jack Kerouac's novel On the Road.
- A Little Miracle
24 December 1962: On Christmas Eve, Sam reenacts A Christmas Carol to remind a millionaire financier (Charles Rocket) that there is more to life than material wealth. Otherwise, a badly needed Salvation Army hostel will be demolished.
4 July 1964: It's the eve of the feminist revolution and Sam has leapt into the body of 13-year-old Butchie Rickett, who must keep his mother (Sandy Faison) from running out on her family.
- 8 1/2 Months
15 November 1955: Having leaped into the body of 16-year-old Billie Jean of Claremore, Okla., Sam finds himself in labor and on a mission to stop her from losing her baby through adoption.
- Future Boy
6 October 1957: Sam becomes sidekick to Captain Galaxy, a popular '50s TV character, and must prevent the star, eccentric actor Moe Stein, from being committed to a mental institution due to his obsession with a time machine he has built a device that curiously parallels Sam's own "ball of string" theory, which serves as the basis for Project Quantum Leap....
- Private Dancer
6 October 1979: Sam leaps into the body of a male stripper who must steer a deaf girl (Beriault) toward a professional dancing career.
- Piano Man
10 November 1985: Tickling the ivories in a crowded nightclub, Sam has leaped into the body of Chuck Danner, whose former music partner and ex-girlfriend has found him again after a three-year search. But she is not the only one looking for Chuck, as an exploding car is soon to prove.
- Southern Comforts
4 August 1961: Blowing out birthday candies in a New Orleans bordello may be Al's idea of heaven, but Sam has 24 hours to save one of the girls (Georgia Emelin) from a grisly death.
- Glitter Rock
12 April 1974: English rock band King Thunder is performing in front of 80,000 screaming fans when Sam leaps into the body of their lead singer, Tonic.
- A Hunting Will We Go
18 June 1976: Sam finds himself in the body of a professional bounty hunter handcuffed to a woman (Jane Sibbett) accused of a million-dollar embezzlement.
- Last Dance Before An Execution
12 May 1971: Sam finds himself in the body of a convicted murderer, strapped into the electric chair. Given a last-minute reprieve, Sam has 48 hours to prove him innocent.
- Heart of a Champion
23 July 1955: Sam leaps into the body of wrestling tag-team brother Terry Sammis, who must save his sibling Ronnie from dying of heart failure during a title fight.
- Nuclear Family
26 October 1962: Sam becomes a 19-year-old at the height of the Cuban missile crisis. With people expecting annihilation at any moment, he has to prevent a senseless killing caused by hysterical panic.
- Shock Theater
3 October 1954: Sam leaps into the body of a manic-depressive patient at the Havenwell mental institution. His task is to assist another patient, but Sam is having trouble keeping his own mind clear in the face of a sadistic orderly (Young) who gives him unprescribed shock therapy allowing several of Sam's old leapt-into personas to come to the fore, resulting in a cliffhanger ending involving Sam and Al's respective roles.
- The Leap Back
18 September 1999 / 15 June 1945: Sam and Al, leaping through time simultaneously, have changed places. Sam, now a hologram to Al, is reunited at Project Quantum Leap with Donna, the wife he had forgotten existed due to his "Swiss-cheesed" memory. Meanwhile, back in 1945, Al must prevent the deaths of former POW Tom Jarret and his fiancι.
- Play Ball
6 August 1961: Sam leaps into the life of Lester "Doc" Fuller, an ex-major-league baseball pitcher now eking out a living on a minor-league team, and helps him back to the big time while also reuniting a young pitcher with his estranged father.
17 August 1969: Jackson Point, Miss.: Sam becomes Sheriff Archie Necaise and must save his girlfriend Cissy from getting killed by the approaching Hurricane Camille.
11 May 1965: Much to his disgust, Sam finds himself a member of the Ku Klux Klan. His mission, however, is to prevent the lynching of an African-American rights activist.
- Permanent Wave
2 June 1983: Sam becomes a hairstylist and must protect a mother and her young, disabled son (Joseph Gordon-Levitt) after the boy witnesses a shooting.
20 June 1980: Sam experiences the pressures exerted on a date-rape victim who is made to feel guiltier than the perpetrator.
- The Wrong Stuff
24 January 1961: In perhaps his most unusual leap, Sam finds himself in the persona of Bobo, a chimp in the space program, who is destined to die instead in a cruel crash-helmet research project.
28 February 1979: Sam leaps into the body of Lt. Jack Stone, a police officer investigating a gruesome murder. Strangely affected by something terrible that happened to Stone, he must overcome his feelings to identify the killer and save his own life.
- A Single Drop of Rain
7 September 1953: Sam has leaped into the life of Billy Beaumont, a traveling rain-maker. His mission is to save Billy's brother's marriage.
- Unchained a.k.a. Unchained Melody
2 November 1956: Sam leaps into the persona of Chance Cole, a 40-year-old prisoner sentenced to nine months on a chain gang for passing bad checks. He must prove the innocence of a fellow inmate, wrongly convicted of armed robbery.
- The Play's the Thing
9 September 1969: Sam awakes to find himself a struggling young actor and the boy-toy of an older woman who wants to make it as a singer, but whose straitlaced son wants her to return to a life of dull domesticity.
- Running For Honor
11 June 1964: Sam becomes a brilliant naval cadet whose roommate has been run off campus by a gay-bashing clique.
- Temptation Eyes
1 February 1985: Sam leaps into the persona of a TV news anchor who becomes the unwitting confidant of a killer responsible for a series of gruesome murders in San Francisco's Chinatown. Sam also falls in love with a psychic who is able to see him as he really is.
- The Last Gunfighter
28 November 1957: Sam becomes 82-year-old Tyler Means, the aging hero who cleaned up the town of Coffin, Ariz., by shooting the infamous Claggett brothers. But Tyler's claim to fame is challenged by a man from the past, seeking revenge.
- A Song for the Soul
7 April 1963: Sam becomes Cheree of the Lovettes singing group and must stop one of the girls from leaving school and running away from her disapproving father to try to make it as a singer.
- Ghost Ship
13 August 1956: Sam finds himself flying a private plane through the Bermuda Triangle to reach Bermuda before one of his passengers dies of a burst appendix.
27 January 1982: Sam becomes Roberto, a TV talk-show host with an abrasive attitude toward his colleagues. But as an investigative reporter, Roberto seeks to uncover the source of deadly gases being produced at a nearby pesticide plant.
- It's A Wonderful Leap
10 May 1958: Sam becomes a New York cabbie and accidentally runs over a woman who says she is a guardian angel sent to stop him from getting shot by robbers. What's more, she can see Al.
- Moments to Live
4 May 1985: Sam finds himself in the persona of a TV soap-opera star kidnapped by an obsessed fan who wants to have his child.
- The Curse of Ptah-Hotep
2 March 1957: Sam leaps into the body of Dale Conway, an archaeology professor exploring an Egyptian tomb where he is due to disappear, along with his attractive 32-year-old colleague (Darr).
- Stand Up
30 April 1959: Sam becomes a nightclub singer who must save his comedian partner, Mack (Bob Saget), from being killed when a powerful club owner takes a liking to Mack's girlfriend (Amy Yasbeck).
- A Leap for Lisa
22 June 1957: Sam leaps into the body of Al as a young naval pilot (with the nickname Bingo) and must prove he did not rape and murder the kinky wife (Debbie L. James) of his commanding officer (Charles Rocket). But after his alibi, the adulterous nurse Lisa, dies in a car crash, the trial goes badly and hologram Al disappears replaced by a new observer (Roddy McDowell).
- Lee Harvey Oswald
5 October 1957 to 22 November 1963: In a two-hour episode to commemorate the 30th anniversary of President John F. Kennedy's assassination, Sam leaps into Lee Harvey Oswald, taking on the accused killer's personality and volatile emotions while affecting key events in his life leading to JFK's death. The character of "Sgt. Bellisario" reflects series creator Bellisario's claimed real-life brush with Oswald in the military.
- Leaping of the Shrew
27 September 1956: Sam is swept away (and castaway) as a Greek sailor shipwrecked with a beautiful but spoiled rich girl.
- Nowhere to Run
10 August 1968: Sam inhabits the persona of a legless Vietnam veteran undergoing therapy at a hospital, where he is befriended by a young volunteer nurse. But he must overcome a brutal and unsympathetic orderly to stop a paralyzed-from-the-neck-down young soldier (Michael Boatman) from drowning himself in despair.
- Killin' Time
18 June 1958: Sam leaps into the life of mass murderer Leon Stiles, who has escaped custody and taken a mother (Connie Ray) and her young daughter hostage in their home, which is surrounded by police. Meanwhile, in the Imaging Chamber, the confused but desperate Stiles steals a guard's gun and escapes onto the streets. Sam must reluctantly hold on to his hostages telling them the truth of his time-traveling to keep himself alive while Al tries to recapture Stiles.
- Star Light, Star Bright
21 May 1966: As 79-year-old Max Stoddard, Sam must prove he has seen a UFO so his family does not have him committed to a mental institution. He must also cope with the attentions of two government agents whose investigations into Max's claims could force Sam to reveal details of Project Quantum Leap. He also finds time to play Hendrix's version of "The Star Spangled Banner" on his amazed teenage grandson's electric guitar and pass on a warning about the dangers of drug abuse!
- Deliver Us from Evil a.k.a. Evil Leaper 1
19 March 1966: This time Sam leaps back into the persona of Down's Syndrome sufferer Jimmy La Matta (from the season-two episode "Jimmy") with a mission to save the marriage of Jimmy's brother, Frank, and his wife, Connie. But dark forces are at work in the guise of another leaper the wicked Alia and her hologram observer, Zoey. Alia has leaped into Connie's persona with the mission of getting Jimmy institutionalized.
- One Little Heart a.k.a. Trilogy, Part I
8 August 1955: As Louisiana sheriff Clayton Fuller, Sam takes the first leap in a trilogy concerning the loves and tribulations of Fuller's 10-year-old daughter, Abagail, who is accused of two murders. Fuller's wife, Laura, is in a mental asylum, and Sam learns Laura's mother killed all her children except Laura, then committed suicide. The simple townsfolk believe the family is cursed, and a crazed widow is out for revenge.
- For Your Love a.k.a. Trilogy, Part II
14 June 1966: Sam leaps into Will Kinman, the teenager from Part I, who is now a deputy sheriff. He and 21-year-old Abagail are about to marry when the child she has been babysitting disappears and because of lingering suspicions, she is once again accused of murder.
- The Last Door a.k.a. Trilogy, Part III
28 July 1978: In the final part of this trilogy, Sam leaps into elderly attorney Lawrence Stanton, who must prove 33-year-old Abagail's innocence when she's put on trial for the murder of Leta Aider. Sam also discovers that Abagail's daughter, Sammy Jo, is his child and the little girl's life threatens to be one of terrible hardship.
- Promised Land
22 December 1971: Sam returns to his hometown of Elk Ridge, Ind., as Bill Walters, who, with his two brothers, is holding up the town's bank for the exact amount of money owed by the Walters' farm.
- A Tale of Two Sweeties
25 February 1958: Sam leaps into Marty Ellroy, who's wed to two women and has two children from each marriage. Sam believes he must make Marty select one wife over the other and save Marty from his excessive gambling problem. Eventually, however, it is the wives who make the decision for him.
16 October 1968: Sam leaps into the life of Margaret Sanders, a housewife who joins her daughter in the fight for equal rights for women. Sam must save Margaret's marriage to her old-fashioned husband George, and stop their daughter, Suzi, and Suzi's radical associate, Diana, from being killed at a sit-in.
- Dr. Ruth
25 April 1985: Sam becomes sex counselor Dr. Ruth Westheimer and helps a radio-show caller fight sexual harassment while also playing matchmaker to a young sparring couple. Meanwhile, back in the Imaging Chamber, Dr. Ruth is helping Al sort out his love life.
- Blood Moon
10 March 1975: Sam gets a taste of horror when he steps into the life of Nigel Covington (Ian Buchanan), an eccentric London artist who believes he is a vampire and is planning to sacrifice a woman and drain her blood at the Blood Moon ritual.
- Return of the Evil Leaper a.k.a. Evil Leaper II
8 October 1956: Sam leaps into the persona of Arnold Watkins, a college freshman who has been disguising himself as the Midnight Marauder and protecting the innocent from danger. Sam must stop him from killing himself in a suicidal stunt. But "evil leaper" Alia has leaped into another student, prompting Sam to try and convince Alia to change her ways and leap out in tandem with him.
- Revenge of the Evil Leaper a.k.a. Evil Leaper III
16 September 1987: Sam and Alia leap into the personae of prisoners in a women's jail. Alia's Observer, Zoey, has become a leaper herself as the prison's warden and is determined to track them down with the help of her computer, Lothos.
- Goodbye Norma Jean
4 April 1960: Sam leaps into Dennis Boardman, Marilyn Monroe's chauffeur, and must save her from killing herself before she makes her last movie.
- The Beast Within
6 November 1972: Sam leaps into the persona of a homeless Vietnam veteran, to save the lives of Roy Brown, a high-school buddy and troubled fellow veteran; and Daniel Burke, the 13-year-old son of another classmate. And apparently, Sam gets a discreet helping hand from Bigfoot!
- The Leap Between The States
20 September 1862: Sam is shocked to find he's landed in the middle of the Civil War as a Union infantry officer and he's even more shocked when he gets shot. Al tells him he's in 1862 Virginia, and has become his own great-grandfather, Captain John Beckett. His mission is to make sure his great-granddaddy marries his great-grandma, Olivia, a Southern aristocrat and also to save the life of a slave named Isaac, who is destined to have a very famous grandson in the Civil Rights movement.
- Memphis Melody
3 July 1954: Sam leaps into the persona of Elvis Presley two days before he is signed by Sam Phillips of Sun records. He not only has to ensure Elvis gets his contract but also that a nervous girl singer, Sue Anne Winters, also gets the chance to follow her dream.
- Mirror Image
8 August 1953: An enigmatic leap lands Sam in a Pennsylvania tavern, as his own grown self on the day of his birth. As Al and Gushie work frantically to locate him, Sam befriends a wise bartender (McGill) and a group of coal miners. As a host of familiar-looking faces pass through the bar with different identities than Sam remembers Sam ponders his life of leaping with Al the bartender, who tells Sam he controls his own destiny. Pressed for more, Al the bartender simply shrugs and says, "Sometimes, 'that's the way it is' is the best explanation." Sam realizes he must right at least one more wrong before he can go home, and leaps back to tell Al Calvavicci's wife Beth (from "M.I.A.") to wait for Al, who will survive Vietnam and come home to her. The closing title cards state that Beth and Al have four daughters and will shortly celebrate their 39th wedding anniversary ... and that Sam Beckett never returned home.