Steve Smith was recruiting cast members, especially a sidekick, for his new project, The Red Green Show.

He had come to Second City and was checking out the entire troupe, but when Patrick did his twitchy-nerd character, Smith knew he had his sidekick.

In 2006, McKenna played producer Jeffrey Littleman on the short-lived CBC television series Getting Along Famously.

In late 2011, he played the politician and Canadian Confederation leader Alexander Galt in the CBC television movie John A: Birth of a Country.

Throughout the mid-2000s and early 2010s, McKenna saw work as a voice actor in Canadian animated series such as Atomic Betty, Iggy Arbuckle, Crash Canyon and Sidekick.

McKenna has become involved with many charity organizations and causes—including wheelchair athletes, Adult ADHD, MS Society, Lupus Canada and McMaster Sick Kids—some of which he has personal connection with.

McKenna suffered a debilitating back injury in the early 2000s that left him unable to walk for a year.

Brendon McKenna was seen in two episodes, Dancing with Mr. D. and The Unseen Lever, of his father's series Traders as Marty's son, Mark Stephens.