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 Kevin Sussman Stuart Guest Star Christine Baranski Dr. Beverly Hofstadter Guest Star Laurie Metcalf Mary Cooper Guest Star Judd Hirsch Dr. Alfred Hofstadter Guest Star Keith Carradine Wyatt Guest Star Katey Sagal Susan Guest Star Jack McBrayer Randall Guest Star Dean Norris Colonel Richard Williams Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer Steven Molaro Executive Producer Steve Holland Writer Tara Hernandez Writer Steve Molaro Writer Eric Kaplan Writer Jim Reynolds Writer Mark Cendrowski Director