The president said deputy press secretary Josh Earnest will take over at the podium.
"In April, Jay came to me in the Oval Office and said that he was thinking of moving on, and I was not thrilled, to say the least," Obama said Friday at the surprise announcement. "But Jay has had to wrestle with this decision for quite some time."
"I will continue to rely on him as a friend and an adviser after he leaves to spend as much of his summer as he can with his kids before he decides what's next for him," he said. "Whatever it is, I know he's going to be outstanding at it."
Obama called Carney "one of my closest friends" and Carney said the job had been "an honor and a joy for me."
Calling Earnest a "straight shooter" the president said he is a "person of sound judgement and great temperament."
Carney, who took over for Robert Gibbs in February 2011, isn't even the highest-profile departure for the administration Friday.