What’s My Line? was produced by Mark Goodson and Bill Todman for the
CBS television network. The original series, which was usually broadcast live,
debuted on Thursday February 2, 1950 (above) at 8:00 p.m. ET. After airing
alternate Wednesdays, then alternate Thursdays, finally on October 1, 1950
it had settled into its weekly Sunday 10:30 p.m. ET slot where it would remain
until the end of its network run on September 3, 1967.

That final telecast was the 876th and was highlighted by clips from past shows,
a visit by the show’s first contestants, and the final "mystery guest," who was
John Daly himself (below). What’s My Line? won three Emmy Awards for "Best
Quiz or Audience Participation Show," in 1952, 1953 and 1958 and a Golden
Globe for Best TV Show in 1962. After its cancellation by CBS in 1967, the
show returned in syndication as a daily production which ran from 1968 until
1975.