Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Melissa Rauch Bernadette Rostenkowski Actor Mayim Bialik Amy Farrah Fowler Actor Kate Micucci Lucy Guest Star Kevin Sussman Stuart Guest Star Riccardo LeBron Tom Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer David Goetsch Writer Maria Ferrari Writer Steven Molaro Writer Eric Kaplan Writer Steve Holland Writer Mark Cendrowski Director