"My time as showrunner on 'The Walking Dead' has been an amazing experience, but after I finish Season 3, it’s time to move on," Mazzara said in a statement. "I have told the stories I wanted to tell and connected with our fans on a level that I never imagined. It doesn’t get much better than that. Thank you to everyone who has been a part of this journey."
Executive producer Gale Anne Hurd said she is grateful for Glen's hard work. "I am supportive of AMC and Glen's decision and know that the series is in great hands with one of the most talented and dedicated casts and crews in the business," Hurd said in a statement. "I look forward to the show's continued success."
Mazzara was the second showrunner on the series. He replaced executive producer and creator Frank Darabont during the second season. Whoever replaces Mazzara will be the show's third showrunner in four seasons.
"I am in full support of both AMC and Glen Mazzara in the decision they have come to and believe the parties came to this decision in the best interest of the future of the show," Robert Kirkman, executive producer and co-creator of the Image Comic series the show is based on. "I thank Glen for his hard work and appreciate his many contributions to 'The Walking Dead' and look forward to working with him as we complete post production on Season 3. I am also excited to begin work on another spectacular season of this show that I know means so much to so many people. This show has always been the result of a wide range of extremely talented men and women working tirelessly to produce their best work collectively. I believe the future is bright for 'The Walking Dead.' Thank you to the fans for your continued support."
Under Mazzara's leadership, the zombie apocalypse series broke cable ratings records during Season 3. The premiere had close to 11 million viewers during its first-run broadcast.
"I wanted to broaden the scope," Mazzara told The Huffington Post about Season 3 of "The Walking Dead." "I wanted to get these people out there. I wanted them to feel their back was against the wall, but I wanted them to be stumbling through a desolate world where a prison seems like a reasonable place to hide. We're going to introduce the Governor, we've introduced Michonne. I just wanted a bigger scope. I just wanted to feel that the whole world had gone to hell and our characters were trapped in it."
AMC and Mazzara released a joint statement on the matter:
"Today, AMC announces the season 4 pick-up of "The Walking Dead. "
AMC also jointly announces with Glen Mazzara today that for future seasons, the two parties have mutually decided to part ways. Glen guided the series creatively for seasons 2 and 3. AMC is grateful for his hard work. We are both proud of our shared success.
Both parties acknowledge that there is a difference of opinion about where the show should go moving forward, and conclude that it is best to part ways. This decision is amicable and Glen will remain on for post-production on season 3B as showrunner and executive producer."