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 Stephen Root Dan Guest Star LeVar Burton LeVar Burton Guest Star John Ross Bowie Barry Kripke Guest Star Paul Wilson Professor Sharpe Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer Steven Molaro Executive Producer, Writer Tara Hernandez Writer David Saltzberg Writer Jim Reynolds Writer Steve Holland Writer David Goetsch Writer Mark Cendrowski Director