The Streets of San Francisco

The Streets of San Francisco first aired on September 16, 1972 in a time slot of Saturday at 9 p.m., playing against two popular half-hour shows, Mary Tyler Moore and Bob Newhart. Due to the success of its first season, it moved into a more prominent spot -- Thursdays at 10:00 pm, and later, Thursdays at 9:00 pm, showing in the same time slot as Kojak, Ironside, and Barnaby Jones.

The Streets of San Francisco starred Karl Malden as veteran detective Mike Stone and Michael Douglas as Steve Keller, a rookie detective who is college-educated in a workingman's SFPD.

The show ran for a total of five seasons. After the second episode of the 1976-77 season, Michael Douglas left the show; writers explained that Steve Keller was going to pursue a teaching career. The insufferably pretty Richard Hatch was chosen to play the ingenue-detective role, but the show foundered and lasted for only another season, airing for the last time on June 23, 1977.
From: TV.com