Walter "Walt" Hartwell White Sr. (also known by his clandestine alias
Heisenberg) is a fictional character and the main protagonist of
Breaking Bad, portrayed by
Bryan Cranston. A graduate of the
California Institute of Technology, Walt was once a promising
chemist who cofounded the company Gray Matter Technologies. He left Gray Matter abruptly, selling his shares for $5,000; soon afterward, the company made a fortune of roughly $2.16 billion, much of it from his research. Walt subsequently moved to
Albuquerque, New Mexico, where he became a high school chemistry teacher. After being diagnosed with Stage IIIA
lung cancer, he resorts to manufacturing
methamphetamine and drug dealing to ensure his family's financial security after his death. Series creator
Vince Gilligan has described his goal with Walter White as "turning
Mr. Chips into
Scarface", and deliberately made the character less sympathetic over the course of the series. Walt's transition from mild-mannered school teacher and family man to ruthless criminal mastermind and murderer is the show's central focus.