Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Mayim Bialik Amy Farrah Fowler Actor Melissa Rauch Bernadette Rostenkowski Actor Carol Ann Susi Debbie Wolowitz Guest Voice Kevin Sussman Stuart Bloom Guest Star Wil Wheaton Wil Wheaton Guest Star Brent Spiner Brent Spiner Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer, Writer Steven Molaro Writer Jim Reynolds Writer Eric Kaplan Writer Maria Ferrari Writer Mark Cendrowski Director