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 Keith Carradine Wyatt Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer Steven Molaro Executive Producer, Writer David Goetsch Writer Jim Reynolds Writer Jeremy Howe Writer Steve Holland Writer Eric Kaplan Writer Mark Cendrowski Director