[citation needed] Mazzara left Life to create and executive produce a new series Crash, based on the Oscar-winning film of the same name, on which he served as head writer and showrunner.

[citation needed] In 2009, he joined the medical drama series Hawthorne for two seasons as executive producer and writer.

[2] On July 27, 2011, it was reported that Mazzara had taken over as showrunner of The Walking Dead after Frank Darabont dropped out of the position.

[5] Glen Mazzara is the Creator, Executive Producer, and Showrunner of A&E's series, Damien, based on the classic horror film, The Omen.

On April 15, 2019, Mazzara joined several other writers in firing their agents as part of the WGA's stand against the ATA and the practice of packaging.