Allen also was a regular on the popular panel game show "What's My Line?" from 1953 to 1954, and returned frequently as a panelist until the series ended in 1967, including an appearance on June 19, 1966 as a guest, where the panel failed to guess his line: a motorcycle salesman (Allen at the time was co-owner of a Los Angeles dealership selling Honda motorcycles). Steve was sometimes jokingly referred to as the son of fellow panelist Fred Allen, but the two men were unrelated. He is also credited with reviving and popularizing the phrase "Is it bigger than a breadbox" while questioning contestants on "What's My Line?".