Lehmo began his career in stand-up in the early nineties, infamously going on Hey Hey It's Saturday's Red Faces segment and receieving two zeros and a three from the judges. Lehmo has performed sell-out shows both throughout Australia and in the U.K. He also holds the Guiness World Record for Most Jokes Told in an Hour, after telling 549 jokes.
Lehmann has appeared four times on The Little Dum Dum Club. His first appearance came on the podcast's thirteenth episode. The episode was published on the 18th of January, 2011. He returned 18 months later alongside Michael Chamberlin for the show's 92nd episode. It was posted on June 27th, 2012. After an absence, Lehmo appeared with cartoonist Jason Chatfield in episode 156; followed by an apperance with Ronny Chieng for the show's 172nd episode.