Some of Olson's earliest radio work occurred in the mid 1930's at WTMJ in Milwaukee, where he appeared on the variety show The Grenadiers.

From January 1949 to July 1952, Olson hosted Johnny Olson's Rumpus Room, a daytime television talk show which was the first daytime show broadcast from DuMont's flagship station WABD over DuMont's small East Coast network.

Olson also hosted the Saturday-morning children's show Kids and Company on DuMont from September 1951 to June 1952, with co-host Ham Fisher.

[7]: 288-289 Olson was host of Homemaker's Jamboree, an audience-participation game show that debuted on WJZ-TV on October 5, 1952.

The following year, he added duties on sister show What's My Line?, and in 1962 began announcing on the original Match Game in daytime on NBC until that series ended in 1969.

His involvement with those shows ended when he was designated announcer of the 1972 revivals of The Price Is Right and I've Got a Secret, both of which were taped in Hollywood, where he relocated.

[10] In addition to serving as host Bob Barker's sidekick, Olson was a beloved and valued member of the "cast".

became a catchphrase, and a The Price Is Right tradition observed by his successors Rod Roddy (1986–2003), Rich Fields (2004–2010) and George Gray (2011–present).