Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Kaley Cuoco Penny Actor Brian Patrick Wade Kurt Guest Star Rachel Cannon Patty Guest Star Erin Allin O'Reilly Cheryl Guest Star Kimberly Kevon Williams Vicki Guest Star Cynthia Holloway Roberta Guest Star Chuck Lorre Executive Producer Bill Prady Executive Producer David Goetsch Writer David Litt Writer Robert Cohen Writer Mark Cendrowski Director