This page lists the Main Characters on The Big Bang Theory whose names have appeared during the opening credits currently or in the past.
Leonard Hofstadter is the roommate of Sheldon Cooper, husband of Penny Hofstadter, and he works as a experimental physicist doing research at the California Institute of Technology with Sheldon, Howard, and Raj. Leonard is portrayed by Johnny Galecki.
Sheldon Cooper is Leonard Hofstadter's roommate, Amy Farrah Fowler's boyfriend, and he works as a theoretical physicist doing research at the California Institute of Technology with Leonard, Raj, and Howard. Sheldon is portrayed by Jim Parsons.
Howard Wolowitz is Bernadette Rostenkowski's husband, soon to be a father, and he works as an aerospace engineer at the California Institute of Technology with Leonard, Sheldon, and Raj. Howard is portrayed by Simon Helberg.
Rajesh "Raj" Koothrappali is Emily Sweeney's boyfriend, and he works as a astrophysicist doing research at the California Institute of Technology sometimes working with Leonard, Sheldon, and Howard. Raj is portrayed by Kunal Nayyar.
Penny Hofstadter is Leonard Hofstadter's wife, and she currently works as a pharmaceutical sales representative at Zangen with Bernadette. When she first moved in across the hall from Leonard, she was a waitress at The Cheesecake Factory and a struggling actress who had a longer on again and off again relationship with Leonard. Penny is portrayed by Kaley Cuoco.