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 Brian George Dr. V.M. Koothrappali Guest Star Maria Canals-Barrera Issabella Guest Star Christine Baranski Dr. Beverly Hofstadter Guest Star John Ross Bowie Barry Kripke Guest Star Pamela Adlon Halley Wolowitz Guest Voice Brian Posehn Bert Kibbler Guest Star Laurie Metcalf Mary Cooper Guest Star Michelle Arthur Mrs. Petrescu Guest Star Judd Hirsch Dr. Alfred Hofstadter Guest Star Tucker Albrizzi Christopher 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, Writer Steve Holland Writer Saladin K. Patterson Writer David Goetsch Writer Erik Kaplan Writer Tara Hernandez Writer Maria Ferrari Writer Giuseppe Graziano Writer Steve Molaro Writer Eric Kaplan Writer Jim Reynolds Writer Jeremy Howe Writer Anthony Del Broccolo Writer Adam Faberman Writer Mark Cendrowski Director Nicole Lorre Director