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 Andrew Hill Newman Albert Einstein Guest Star John Apicella Archimedes Guest Star Nick Ullett Distinguished Scientist Guest Star Tom Fonss Student Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer Steven Molaro Executive Producer, Writer Eric Kaplan Writer Jim Reynolds Writer Tara Hernandez Writer Steve Holland Writer Maria Ferrari Writer Mark Cendrowski Director