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 Laurie Metcalf Mary Cooper Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer, Writer Eric Kaplan Writer Steve Holland Writer Steven Molaro Writer Howard Murray Director Jim Reynolds Writer