Lasseter, 61, had been on leave from his job for the past six months after he apologized for acting inappropriately at work, particularly hugging and kissing employees without their permission.
The Hollywood Reporter said he has returned and will serve as a consultant with the company through Dec. 31.
"John had a remarkable tenure at Pixar and Disney Animation, reinventing the animation business, taking breathtaking risks, and telling original, high quality stories that will last forever. We are profoundly grateful for his contribution, which included a masterful and remarkable turnaround of The Walt Disney Animation Studios. One of John's greatest achievements is assembling a team of great storytellers and innovators with the vision and talent to set the standard in animation for generations to come," Bob Iger, Disney's chairman and CEO, said Friday.
"The last six months have provided an opportunity to reflect on my life, career and personal priorities," Lasseter said in a statement to Deadline.com. "While I remain dedicated to the art of animation and inspired by the creative talent at Pixar and Disney, I have decided the end of this year is the right time to begin focusing on new creative challenges."
Among the blockbusters Lasseter has shepherded are Toy Story, A Bug's Life, Monsters Inc., Cars, Zootopia, Frozen and Moana.
No replacement has been announced for Lasseter yet.