The character of Rockford was originally written in an unproduced script for the ABC series Toma (1973). That script was rewritten as the pilot for the "Rockford Files." Both ABC (who initially rejected the script for "Toma") and NBC had problems with the "Rockford" scripts. Executives at both networks thought the dramatic series scripts were too funny. The writers were always ordered to take out the funny lines. The writers and eventually the star refused.
The character of Rockford's father was named Joseph; he was named after writer Stephen J. Cannell's father. The name of Rockford was used after Cannell found the name listed in the Universal Studios employee directory.
David Chase, a writer/producer for "Rockford," went on to create The Sopranos (1999). An episode from "The Sopranos" first season shows a scene in a retirement home where the inhabitants are watching television. We can't see what they're watching but we can hear the theme to "Rockford" playing clearly.
The show was a co-production between the production companies of Roy Huggins and James Garner and Universal. Garner sued Universal claiming he was not being paid his share of the syndication profits. After several years of litigation, Universal settled with Garner. Exact terms are not known.
James Garner explained in an interview that Jim Rockford's license plate number, 853-OKG, was created by his agent at the start of the show and stands for August, 1953, when Garner got his first acting job, and OKG which stands for Oklahoma Garner, his home state.
Besides detectives Richie Brockleman and Lance White, other recurring characters on the show were reformed prostitute Rita Kapkovic (played by Rita Moreno), disbarred lawyer John "Coop" Cooper (played by Bo Hopkins), Jim's ex-cellmate Gandolph "Gandy" Fitch (played by Isaac Hayes) and parole officer turned private investigator Marcus "Gabby" Hayes (played by Louis Gossett Jr.).
Rockford's telephone number is shown to be 555-2368 during the opening credits, as his answering machine message is heard just before the music starts. This was also the phone number shown for the Ghostbusters in their in-movie ad.
During the first season, Rockford's trailer moved from a parking lot just off Pacific Coast Highway in Malibu, CA to another Malibu location in an area known as Paradise Cove. The trailer remained at the Paradise Cove location for the remainder of the series. The first location had an address of 22968 Pacific Coast Highway, Malibu, CA - the second had an approximate address of 28128 Pacific Coast Highway, Malibu, CA.
In an early episode from the first season when Jim calls the police station and asks for Dennis he calls him "Lt. Becker." The character became Sgt. Becker for the next several seasons until Dennis got promoted to Lt. later.