- All-Star Cast: The fifth-season premiere, "The Connection," boasted a truly astonishing collection of guest stars, including: Edward Asner (at the same time as he was appearing on The Mary Tyler Moore Show); Robert Reed (at the same time he was appearing on The Brady Bunch); Barbara McNair (a well-known singer who hosted her own variety show, The Barbara McNair Show, for a couple of years); Cleavon Little (who had won a Tony Award for Purlie the year before, and would soon become well-known as Sheriff Bart in Blazing Saddles); Gene Washington (former wide receiver with the San Francisco 49ers); Stefanie Powers (who had starred in The Girl from U.N.C.L.E. and would later star in Hart to Hart); Claudia McNeil (Golden Globe Best Actress nominee in 1961 for A Raisin in the Sun); Cesar Romero (who appeared in hundreds of films and shows but is probably best know these days as the Joker from Batman); and, last but not least, Richard Pryor.
- Cast the Expert: In "Exit the Closer", the make-up man for Hardy's car dealer commercials was played by the series' real-life make-up man, Howard J. Smit.
- Dawson Casting: Despite the series' concept of featuring three "young, hip" cops able to identify with "young people," Pete and Linc were actually played by actors who turned 30 in 1970 and 1969, respectively - making them no younger than most mid-career cops. (Averted with Peggy Lipton, who was only 22 when the series started.)
- Real-Life Relative: Robert Lipton, Peggy's brother, guest-starred in the episode "Crime Club".
- Dan Spelling, Aaron Spelling's brother, guest-starred in the episodes "Confrontation!", "Suffer, Little Children" and "Scion of Death".
- Written by Cast Member: Tige Andrews co-wrote the first season episode "Love".
- You Look Familiar: Quite a few actors appeared three or four times as different characters, including Lou Gossett, Jr. and Edward Asner.
Trivia / The Mod Squad