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 Pamela Adlon Halley, O.C. Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Steven Molaro Executive Producer, Writer Tara Hernandez Writer Giuseppe Graziano Writer Steve Holland Writer David Goetsch Writer Mark Cendrowski Director