Frank Cannon was a private detective in Los Angeles California. He was a former detective with the Los Angeles Police Department, but retired after his wife and son were killed in an automobile accident. It was after his retirement from the police department that Cannon opened his private investigation practice. Cannon liked to drive expensive cars. The car he drove most often was a 1972 ice-blue Lincoln Continental Mark IV
In addition to expensive cars Cannon liked to indulge in expensive food. The indulgence in fancy food may have contributed to the fact that Frank Cannon was very noticeably overweight. During the early years Cannon smoked a pipe, but the pipe smoking diminished around the third season and then disappeared completely.
There were times when Frank Cannon would get hurt during the show. He may be beaten or shot or knocked unconscious. When he apprehended a suspect he might use some judo holds or karate chops or sometimes he would knock down a villain using his big belly as a weapon.
The Cannon series aired for 5 seasons from 1971 to 1976. The role of Frank Cannon was played by William Conrad.