In January 2013, Gimple was named showrunner of The Walking Dead, replacing Glen Mazzara. He served as showrunner from the fourth season to the eighth season. During his tenure, he also became an executive producer for Fear the Walking Dead. Gimple left his role in 2018 to become the chief content officer for The Walking Dead and Fear the Walking Dead, Gimple has also worked on Disney's Pepper Ann and as a writer for The Simpsons comics, including editing the Simpsons' Episode Guidebook "The Simpsons Forever!: A Complete Guide to Our Favorite Family... Continued". He created the cartoon Fillmore! and the comic book Heroes Anonymous with Bill Morrison.