Jackson was one of the last remaining fixtures of the long-running reality series. He started on Idol as one of the original judges, along with Simon Cowell and Paula Abdul, but moved into a mentoring role in Season 13. Jackson's departure leaves host Ryan Seacrest as the only original face from the show's beginnings.
"Randy has been such an integral part of American Idol since Day 1, both as a judge and as a mentor," Idol producers FremantleMedia North America and 19 Entertainment said in a statement. "He's provided great advice and support, shaping the success of so many Idols we have discovered over the years. We wish him all the best in his next chapter. Randy will always be part of our Idol family and we hope he'll visit from time to time."
Current American Idol judges Jennifer Lopez, Keith Urban and Harry Connick Jr. are all returning next year.
On the Set! Supernatural stars share scoop on the 200th episode: