Jake and the Fatman

The character of Fatman was modeled on a role William Conrad played as an aging prosecutor in a two-part episode of Matlock during its first season on NBC, which inspired executive producers Fred Silverman and Dean Hargrove to build a new CBS show around him.

Joe Penny also guest starred in the two-part Matlock episode that inspired the series, though in that story his character was on the opposite side of the legal case from Conrad's character.

After Magnum, P.I. ended, Jake and the Fatman relocated its setting from Los Angeles to Honolulu for the second and third seasons and half of the fourth season, reusing some of Magnum, P.I.'s production sets before returning to Los Angeles for the rest of its run.

J. Michael Straczynski was hired as an executive story consultant after pitching a story built around letting William Conrad sit down for almost every scene, joking that the show's real slogan was 'He can't act, he can't walk, together they fight crime.'

Joe Penny lost a large amount of weight after the show's move to Hawaii, sparking rumors about his health, including speculation that he had AIDS; in reality he was suffering from a gastrointestinal virus and struggled to regain the weight.

When the series later moved back to Los Angeles, it was rumored to have happened at Joe Penny's request, which he denied.

The show's fourth-season episode 'It Never Entered My Mind' introduced Dick Van Dyke as Dr. Mark Sloan, a crime-solving physician, and its success led first to three TV movies and then to the spin-off series Diagnosis: Murder, which debuted in 1993.