Born in Springfield, Ohio, McCullough met his future partner Bobby Clark in elementary school.

Due to the White Rats strike of 1916, Clark and McCullough were forced to enter into the burlesque circuit to continue working.

In 1922, the team achieved mainstream stardom in Irving Berlin's Broadway show Music Box Revue.

In many of their films, McCullough's input was severely limited to a supporting role as Clark's antics generated the bulk of the humor.

Around the Fox studio lot, the duo's film series were mockingly referred to as The Clark and McCullough Tragedies.

[3][4] RKO attempted to remedy this by hiring big name directors and granting bigger budgets, but the shorts continued to be panned.

In early 1936, before production was set to begin, Bobby Clark returned to his wife in New York for a short rest while McCullough traveled to Massachusetts.

[6] Upon his release on March 23, McCullough's friend Frank T. Ford picked him up to drive him to the home he shared with his wife in Brookline.