“It was not your business; it’s nobody’s business other than mine,” Christie told reporters at a press conference.
The GOP governor is seen as a potential candidate in the 2016 presidential race, but Christie has sought to tamp speculation that he underwent the medical procedure with an eye on his political future.
“I did this for myself, my wife and my children. And unlike some of you, they will still pay attention to me whether I run for president or not,” he said. “So the fact is that it has nothing to do with running for governor this year, with running for president at any time in my life, if I decided to do that.
“It may sound odd to some people but this is a hell of a lot more important to me than running for president,” he added.
Christie also said the procedure took under an hour, and it did not undermine his work as governor.
“I was asleep for a total of 40 minutes,” he told reporters.
Christie has previously addressed health concerns over his weight, rejecting criticism that it could affect his work.