Jackson, who has been with the Fox musical reality show since its start, will not return for the upcoming 14th season of the series, said the Hollywood Reporter.
"Randy has been such an integral part of American Idol since Day 1, both as a judge and as a mentor. 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," Fox, Idol producers Fremantle Media North America and 19 Entertainment said in a statement.
Judges Jennifer Lopez, Keith Urban and Harry Connick Jr will be back for season 14.