Series debut of Noah Beery Jr. as Joseph 'Rocky' Rockford. Beery replaced Robert Donley, who played Rocky in the pilot.
Apparently Stephen J. Cannell liked the name Tawnia Baker, as he had used it on three of his shows. On the 1973 Columbo episode "Double Exposure" (written by Cannell), the character Tawnia Baker was played by Arlene Martel; in this episode, Tawnia is played by Julie Sommars; then the character name turns up again on The A-Team (1983), being played by Marla Heasley on ten episodes of season two.
This was the series' first official regular episode, and as such, it's the first to feature a humorous answering machine message--which became a noted trademark the series used at each episode's opening. This one says: "Jim, it's Norma, at the market. It bounced. You want us to tear it up, send it back, or put it with the others?" The two hour pilot wasn't an official episode. Later for original syndication it was split into two episodes and numbered: Season 1, Episode 0, Parts 1 and 2. Both parts of Episode 0 feature the exact same machine message, which was borrowed from a Season 6 episode. Now that the series has appeared on Netflix, the IMDb network, and the Peacock streaming service, the episodes are renumbered, and the pilot (entitled Backlash of the Hunter (1974), with both parts entitled with the same name) is Season 1, Episodes 1 and 2, and this episode, "The Kirkoff Case," has been bumped up to Season 1, Episode 3, with all episodes of Season 1 bumped up by two, making it the only season of "The Rockford Files" with 25 (but really 24) episodes, with all other seasons (except the shortened Season 6, with 12) having 22 episodes.
First official show of the series (after the two-hour pilot) and already the show is on its second Firebird, although there is no mention in dialogue that the first Firebird had been replaced. (Identical model in light brown, but the official Pontiac color name was 'Sierra Gold.') The first one was shot up in the pilot during the airplane with machine gun versus Jim's Firebird and Jim's snub nose .38 . Even in this one, he loses use of it for a while after thugs bust out his headlights (and one of his teeth). For the rest of the show he drives a (rented) Chevy Caprice Classic (upgraded Impala) and Tawnia's red Mercedes 450SL convertible.
Executive Producer Roy Huggins had originally designed 'The Kirkoff Case' for his series Toma (1973) as an episode entitled 'How to Get Away with Murder.' Because that segment was never produced, Huggins took his story and reworked it as this Rockford episode. (from "Thirty Years of The Rockford Files" by Ed Robertson)