In The Big Bang Theory Season 10 season premiere episode ‘The Conjugal Conjecture,’ everyone tries their best to deal with the awkward fact that Sheldon’s mother Mary (Laurie Metcalf) and Leonard’s father Alfred (Judd Hirsch) hooked up. Luckily, the gang gets distracted by Penny’s (Kaley Cuoco) family who’s in town for Penny and Leonard’s wedding. BBT fans get to meet Penny’s neurotic mother Susan (Katey Sagal!) and drug dealing brother Randall.
Randall is portrayed by Jack McBrayer. He’s best known for his role as NBC Page Kenneth Parcell on 30 Rock. Since then he’s appeared on several TV shows including The Middle (as Frankie Heck’s boss, dentist Ted Goodwin) and has provided the voices of Irving DuBois on Phineas and Ferb and Pirate Mummy on Jack and the Never Land Pirates, among othe. The Big Bang Theory airs Mondays at 8pm on CBS.