Fenneman's most enduring role was as announcer and sidekick for Groucho Marx on over 200 episodes of the popular game show, You Bet Your Life, which ran throughout the 1950s until 1961. Fenneman was the foil and straight man for Groucho's comedy and wisecracking while at the same time managing the flow of the show as announcer.
He appeared weekly on the Dragnet radio show and, along with co-announcer Hal Gibney, Fenneman was as much a part of the show's iconic sound as its star, Jack Webb.
In the early 1950s he donated a full-sized school bus to the McKinley
Home for Boys located in Van Nuys, California.
Attended and graduated from San Francisco Polytechnic High School in San Francisco, California.
He was awarded a Star on the Hollywood Walk of Fame for Television at 1500 Vine Street in Hollywood, California on October 7, 1981.
Received his Bachelor of Arts degree in Speech and Drama from San Francisco State College (1942).