The premise of Quantum Leap was inspired by films like Here Comes Mr. Jordan (1941) and Heaven Can Wait (1978), as well as the 1960s TV series The Time Tunnel. Creator Donald P. Bellisario saw its potential as an original anthology series, even though similarly themed shows were unpopular with major networks at the time.

The series theme was written by Mike Post and was rearranged for the fifth season, except for the series finale episode, which used the original theme music. Episode scores were composed by Post and Velton Ray Bunch.

The 1993 soundtrack album was dedicated to actor John Anderson, who had played Pat Knight in the episode 'The Last Gunfighter.'

When Quantum Leap was released on DVD, fans discovered that many songs had been replaced from the original soundtrack due to music rights issues; only the fifth season release included all the original music, and later Blu-ray/DVD re-releases restored most of the original songs for all seasons.

At the end of season five, Bellisario was asked to write an episode that could work as either a season finale or series finale, since it was unclear if the show would be renewed; when it wasn't, two closing title cards were added to explain the fates of Al and Sam.

A script for an alternate ending was leaked online years after the finale aired, suggesting Al would become a leaper to find Sam; Bellisario denied any such script existed. In 2018 fan Allison Pregler found on-set publicity stills showing Al and Beth together, and in 2019 lost footage surfaced on Reddit, which Scott Bakula confirmed was authentic, revealing multiple endings had actually been filmed.

Duncan Jones, director of the 2011 film Source Code, said the script reminded him of Quantum Leap and cast Scott Bakula in a voice cameo as a tribute, giving him the line 'Oh, boy.'

In the 2019 film Avengers: Endgame, the character Scott Lang references Quantum Leap as an example of time travel fiction where one can change one's own past.

Dean Stockwell reunited with Scott Bakula as a guest star in special episodes of Star Trek: Enterprise ('Detained', 2002) and NCIS: New Orleans ('Chasing Ghosts', 2014), both series in which Bakula was the lead; 'Chasing Ghosts' was directed by James Whitmore Jr., who had directed 15 episodes and acted in three episodes of Quantum Leap.

For the 2022 revival series, Scott Bakula was asked by producers to reprise his role as Sam Beckett but turned it down, calling it a difficult decision since the original show remained close to his heart.