The Big Bang Theory Cast: Where Are They Now?

15. Brian Thomas Smith - Zack Johnson

Minor characters are an extremely important factor when it comes to making a sitcom as outstanding as can be. What better way to incorporate one of these lesser appreciated names than by having him marry one of the main five characters?

Brian Thomas Smith's portrayal of the ditzy Zack Johnson made for joyful watching, particularly when he was in scenes with the often too smart group of four. First appearing in The Lunar Excitation towards the end of the third season, Zack becomes the on-again, off-again boyfriend of Penny, who ends up becoming his wife following a drunk wedding ceremony they partook in, which was mentioned during season seven's Thanksgiving episode.

After his last official TBBT appearance in the final season, Brian has remained on our screens in small roles, most notably in the 2019 film Babysplitters under the role of Dr Palmer. Aside from this, Smith hasn't been seen too much on television, appearing in just one episode each of The Neighborhood and 9-1-1: Lone Star as Ed and Andrew Reynolds respectively.

His IMDB page also indicates Brian will be appearing in the drama Big Muddy under the guise of Bo Bartlett, which his due for a September release, alongside his role as Christopher in UDrive Me. The new comedy series is currently in the pre-production stage, and everything going on in the world right now, there's no word yet on when work can continue.