The only 1971 debut network show renewed for a second season

Countries & Cities · Published 12 October 2026 Swipe more like this →

In short: In a rare feat of television history, the detective series Cannon achieved something nearly impossible: it was the sole new prime-time debut on its network to be granted a second season. While other shows vanished after one year, this veteran investigator carved out a permanent home in the 1970s.

Debuting as a TV movie on March 26, 1971, Cannon quickly transitioned into a regular series for the 1971–72 season. Television records show this production stood alone as a 1971 network premiere granted a subsequent year, being the sole debut of that era to receive such an extension. While Columbo also saw a renewal, it was part of an existing mystery movie package rather than a standalone series.

The show centered on Frank Cannon, portrayed by William Conrad as a Korean War veteran and former LAPD officer who became a private detective after his wife and son were killed in a bomb attack. Unlike many procedural leads, Cannon was characterized by an unusually high level of education, possessing extensive knowledge of science, art, and history, alongside his skills in marksmanship and hand-to-hand combat.

The series navigated shifting time slots and ratings over its five-season run. It initially aired on Tuesday nights at 9:30 pm following Hawaii Five-0 before moving to Wednesday nights. Despite three consecutive seasons in the Top 20 Nielsen ratings, the show eventually fell to 39th place in season five—a decline attributed to an increase in plot violence and controversial themes—leading to its cancellation.

The production also featured unique technological props for the era, such as a Motorola IMTS car phone. In a pre-cell phone world, these were very rare precursors to modern mobile devices. The series maintained high production value through various guest stars and tie-in novels, including a series of nine original books published in the 1970s.

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