The Big Bang Theory originally aired on the U.S. network CBS.
CBS premiered the sitcom on September 24, 2007, after ordering a reworked version of the pilot. The series was produced by Chuck Lorre Productions and Warner Bros. Television, and it ultimately became one of CBS’s defining comedy hits. Its original U.S. run concluded with its 279th episode on May 16, 2019.
The show’s path to broadcast was not completely straightforward. An earlier pilot featured a different female lead and a substantially different setup, but CBS gave the creators an opportunity to rework the concept. The revised pilot introduced Penny, played by Kaley Cuoco, and became the basis for the long-running series viewers know.
CBS is the original broadcaster, but later distribution can cause confusion. The program entered syndication on local stations, gained cable exposure through TBS, and became available through streaming services in different markets. Those later outlets did not change its original network home. Fox, ABC, and NBC were all major U.S. broadcast competitors, but none originally aired The Big Bang Theory.