The singer had a six-hour operation last week to remove several kidney stones which were too large to have passed through his system.
Phillips has now confirmed his release from a Los Angeles medical centre and assured fans that he's on the mend, reports E! News.
"I'm out of the hospital and back to work. Looking forward to the future," the singer declared.
Phillips's procedure had previously been postponed in May when he fell ill with a severe sinus infection.
The singer apparently underwent eight operations in the run-up to winning American Idol over Jessica Sanchez.
Watch Phillip Phillips perform 'We've Got Tonight below: