Leary began working as a comedian at the Boston underground club Play It Again Sam's. However, his first real gig was at the Rascals Comedy Club as part of the TV show "The Rascals Comedy Hour", on 18 October 1990. He wrote and appeared on a local comedy series, "Lenny Clarke's Late Show", hosted by his friend Lenny Clarke and written by Martin Olson. Leary and Clarke both spoke about their early affiliations and influences in the Boston comedy scene in the documentary film "When Standup Stood Out" (2006). During Leary's time as a Boston-area stand-up comic, he developed his stage persona.