Cannon
Cannon is a CBS detective tv series produced by Quinn Martin which aired from March 26, 1971 on March 3, 1976. The main protagonist would be that your title character, private detective Frank Cannon, played with William Conrad. He appeared on two episodes of Barnaby Jones.
Cannon is your first Quinn Martin-produced string to be aired on a network other than ABC. A"revival" tv picture, The Return of Frank Cannon, was aired on November 1, 1980. In total, there were 124 episodes.