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 Brian Smith Zack Guest Star Rati Gupta Anu Guest Star Lindsey Kraft Marissa Guest Star Eric Nenninger Neil Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer, Writer Steven Molaro Executive Producer Jeremy Howe Writer Adam Faberman Writer Steve Holland Writer David Goetsch Writer Maria Ferrari Writer Mark Cendrowski Director