This is the first episode in which Sam leaps into someone at a time before his birth on August 8, 1953. However, it is still within his lifetime as his mother Thelma would have been five months pregnant with him on April 14, 1953.
Willie Garson plays Seymour in this episode, but also plays Lee Harvey Oswald in Lee Harvey Oswald - October 5, 1957 - November 22, 1963: Part 1 (1992) and Lee Harvey Oswald - October 5, 1957 - November 22, 1963: Part 2 (1992)
After Lt. Lannon lets Sam out of jail, we see elaborate stairs and Sam has a conversation at the news stand with Seymour et alia. The stairs and open area are the atrium of the Bradbury Building in L.A.
Sam says, "It's not gonna be Sam Spade, Philip Marlowe or Thomas Magnum." The reference to Thomas Magnum is an in-joke as Magnum, P.I. (1980) and Quantum Leap (1989) were both created by Donald P. Bellisario.
The title is based upon the "Play it again, Sam" quote that is attributed to Casablanca (1942) but is often misquoted from Rick's quote "Play it, Sam!"
"Play it again, Sam" is also the title of a play by Woody Allen, who appears in this episode.