When the original show (Dragnet (1951)) ended, Joe Friday had been promoted to Lieutenant. However, Jack Webb decided to make Friday a sergeant again for the new series because "few people remember that Friday was promoted toward the end of our run. We think it's better to have Joe a sergeant again. Few detective-lieutenants get out into the field."
Friday's badge number (seen at the beginning and end of each episode) is 714. Badge 714 belonged to Sgt. Dan Cooke, the technical advisor. The badge has been retired and displayed at the LAPD Academy's Museum.
For the sake of continuity, Friday and Gannon always wore the same outfits in every episode. According to Harry Morgan, he and Jack Webb decided to switch coats for one scene to see if anyone noticed. Because only Morgan was in the scene, no one on the set realized it until the scene had been shot. In the next scene, Morgan has on the correct coat. This is the only incident of faulty continuity in the series' run.
Jack Webb had intended to do another revival of the series in 1982. However, because of Harry Morgan's commitments to both M*A*S*H (1972) and its spin-off After MASH (1983) he didn't sign on for the proposed remake. Webb then decided to cast Kent McCord in the role of Friday's new partner; either as "Jim Reed" (the character McCord played on Adam-12 (1968)) or as a new character altogether. Unfortunately, those plans never came to fruition due to Webb's passing due to a massive heart attack in December 1982.
When the revival was in the planning stages, Jack Webb had originally planned on bringing in his former co-star Ben Alexander to reprise his role as Officer Frank Smith. However, Alexander was appearing on the ABC series Felony Squad (1966) and that network would not let him out of his contract to appear on the revival. Webb then chose Harry Morgan to play the new character of Officer Bill Gannon.
During the series' run, there were several references to a fictional department store named Barton's. The store was possibly a stand in for the real life Bullock's, a high end department store chain in Los Angeles, which went out of business in 1996.