Quantum Leap has several references to producer Donald P. Bellisario's previous series, Tales of the Gold Monkey, including a character named "Gushie". "Ghost Ship" featured Captain Cutter, who was the main character in Tales of the Gold Monkey.
Sam has leaped into nine women: a secretary, a divorced mother of three, a beauty pageant contestant, a pregnant teenager, a rape victim, a singer in a teenage girl group, a housewife during the women's movement, Dr. Ruth Westheimer, and an inmate in a women's prison.
Sam Beckett and show creator Donald P. Bellisario both share the same birthday of August 8.
Sam has leaped out of the United States seven times: Egypt, Vietnam, a plane over the Bermuda Triangle, Japan, the Soviet Union, a raft in international waters, and England. If Virginia in 1862 is counted (as it was part of the Confederate States of America at the time), this brings the total to eight.
Sam leaped into the year 1958 eight different times, which made it the most leaped into year during Quantum Leap's entire run.
Sam leaped into every year from 1953 through 1987 at least once, except the years 1977, 1984, and 1986.
Quantum Leap came close to being canceled in its third season due to low ratings. However, a letter writing campaign helped save the series and enabled it to continue for two more years.
Dean Stockwell was the first to "Leap" through time on an episode of the The Twilight Zone- "A Quality of Mercy", playing a war-hungry US Lt. in August, 1945.
Sam Beckett is revealed to have attended MIT, and his friend and guide Al Calavicci is mentioned to have also spent some time there.
Al Calavicci drives two different Ferarris in the series: in "Genesis: Part 1", he is in a red Testarossa (which is shown from very low angles so as to keep the identity of the car hidden), and in "Killin' Time", he is driving a 512 BB Convertible conversion.
Ranked #15 in TV Guide's list of the "25 Top Cult Shows Ever!" (30 May 2004 issue).
The character 'Sam Beckett' was ranked #12 in TV Guide's list of the "25 Greatest Sci-Fi Legends" (1 August 2004 issue).
Season One's cliffhanger into Season Two was the teaser for "What Price Gloria?". The next season, three other episodes premiered before "What Price Gloria?" aired.
There were several ideas for episodes which ultimately were never used. One had Sam leaping in as Robert F. Kennedy. Another idea would involve an animated episode. The producers even toyed with the idea of leaping Sam in as a baby. Also, Donald P. Bellisario wanted to do an episode where Sam leaps in as Thomas Magnum (from Magnum, P.I.). It is unclear why that episode never materialized, although in an earlier episode, a character is seen watching "Magnum, P.I.", thus establishing that show as fiction within the Quantum Leap "universe".
Al's cigar was the idea of actor Dean Stockwell, who said it was "a good way to get free cigars for five years".
Donald P. Bellisario's favorite of all his TV shows.
Scott Bakula ad libbed the line "Oh boy!" at the end of an episode. The producer liked it so much that it became the signature final line of each episode, as Sam finds himself in a new body.
Al's call-sign (pilot nickname) is "Bingo".
Sam leaped outside his life a total of four times. Two of the leaps were explained. In "The Leap Back" Al and Sam traded places due to an accident, which allowed for leaping withing Al's life. "The Leap Between the States" revealed that Sam's great-grandfather had a very similar genetic profile and blood type. Two unexplained leaps before his life were "Play It Again, Seymour" (April 14, 1953) and "The Americanization of Machiko" (August 4, 1953), as the series finale revealed Sam's birth-date as August 8, 1953.
However, both were after he had been conceived (which would have been at the end of 1952), so he did technically exist at that point.
Sam leaps into August 8, 1955 twice ("The Color Of Truth" and "Trilogy, Part, 1").
In "Lee Harvey Oswald", Sam, as Oswald in 1959, has a run-in with a certain Marine named "Bellisario". Series creator Donald P. Bellisario did in fact serve alongside Lee Harvey Oswald in the Marines.
Donald P. Bellisario took the idea for the series from a scrapped premise for Galactica 1980, where the villain would have continued traveling through time after the first episode and the Galactica crew would have to prevent him from altering history for the worse. Which might make this series the only good thing that ever came out of Galactica 1980.
Actor Allusion: When Sam leaps into a college fratboy, the Dean whose office he and his friends regularly break into is called "Dean Stockwell".
A very subtle one in the episode "A Leap for Lisa" with the casting of Roddy McDowall as Sam's guide after Dean Stockwell's Al is Ret Gone. Both McDowall and Stockwell started out as child actors in The Forties who grew up to lead long, respectable adult careers as actors. So in a world where Dean Stockwell doesn't exist, replace him with the actor who has a similar career path but shares next to nothing else in common.
Following the pilot, episodes would open with a Sam voice-over and montage referring in some way to the previous leap. The series abandoned this convention roughly halfway through the second season — likely in order to make it possible to air episodes out of sequence. When the series went into reruns, this trope kicked in — with the stated openings being dropped. They were replaced with the familiar "...will be the leap home" opening narration and the "Oh, boy!" scenes.
In the summer between the first and second seasons, NBC ran a one time only 90 minute recut version of the pilot featuring only the first leap and editing out the baseball leap.
In reruns, the first three seasons always had the opening sequence made for Season 4.
In the version of the pilot aired on G4, the trademark lighting strike that came after Al's line "Yea, well, you ain't Roy Hobbes ether!" is missing. It's such a small cut that it doesn't seem to be made for time reasons.
Hey, It's That Guy!: In "Jimmy," Mr.Blonde got his start harassing retarded dockworkers before working his way up to cutting off cops' ears.
In "Mirror Image," D-Day is the bartender who's more than he seems.
A young Rachel Green plays a hospital volunteer who becomes the leapee's future wife in "Nowhere to Run."
Spencer Hastings and Ishi Nakamura can see Sam as Sam in "Another Mother" and "Temptation Eyes" respectively (and on the soundtrack album version of Dean Stockwell's "Alphabet Rap" from "Shock Theater" - which is thankfully very, very different from the TV version - Spencer is one of the children singing backup).
What Could Have Been: One of the episodes Donald Bellisario was planning for Quantum Leap before it was canceled was for Sam Beckett to leap into Thomas Magnum, thus merging the Quantum Leap continuity with that of Magnum, P.I.. They apparently did film the initial "leaping in" scene, with Scott Bakula in the familiar red Hawaiian shirt turning to the camera and doing Tom Selleck's famous comical eyebrow raise from Magnum, P.I.'s opening credits. This would have resulted in a Celebrity Paradox, since in "Another Mother", a character is seen watching Magnum on TV.
Word of God: Bellisario stated that despite Sam changing history to keep Al and Beth together, the Project would still exist and that Al would remain a crucial part of it.
In the second season finale, "M.I.A.", the tearjerker ending has Al sitting with his wife, who thinks him dead, as she listens to "Unchained Melody" by the Righteous Brothers. She then switches to "Georgia On My Mind" by Ray Charles, and begins dancing alone, and Al joins her as best he can in his hologram form. Briefly, just as the leap occurs, she senses him with her. This scene, particularly with the use of Unchained Melody, may seem to have been heavily inspired by Ghost, but in fact aired May 9 1990, 2 months before Ghost's July 1990 release.