Major cast members in the television show "The Big Bang Theory" include Jim Parsons, Johnny Galecki, Kaley Kuoco and Kunal Nayyar. Debuting in 2007, "The Big Bang Theory" has earned numerous awards and nominations, and continues to be one of the most watched television sitcoms as of 2015.
Jim Parsons, who plays Dr. Sheldon Cooper on "The Big Bang Theory," is a native Texan, having grown-up in the Houston suburb of Spring. Parsons studied theater at the University of Houston and earned a Masters degree in classical theater from the University of San Diego Old Globe Theater. Prior to "The Big Bang Theory," he worked in television commercials, small-market plays, off-Broadway productions and minor television roles. Parsons' role as Dr. Sheldon Cooper has earned him a multitude of awards, including a star on the Hollywood Walk of Fame.
Johnny Galecki's role of Dr. Leonard Hofstadter is not his first experience with "The Big Bang Theory" creator and producer Chuck Lorre. During the late 1980s and early 1990s, Galecki starred on the hit sitcom "Roseanne," which was also a product of Lorre. Two of Galecki's "Roseanne" co-stars, Laurie Metcalf and Sara Gilbert, have also made guest appearances on "The Big Bang Theory." Johnny Galecki's first major acting role was in the movie "Prancer," followed by another film role in "National Lampoon's Christmas Vacation," both in 1989.