Johnny Galecki Leonard Hofstadter Actor Jim Parsons Sheldon Cooper Actor Kaley Cuoco Penny Actor Simon Helberg Howard Wolowitz Actor Kunal Nayyar Raj Koothrappali Actor Eliza Dushku FBI Special Agent Angela Page Guest Star Neil deGrasse Tyson Neil deGrasse Tyson Guest Star Chuck Lorre Executive Producer, Writer Bill Prady Executive Producer, Writer Lee Aronsohn Writer Maria Ferrari Writer Steven Molaro Writer Steve Holland Writer Mark Cendrowski Director