The 38-year-old comic made his exit from the humorous current events program known at a Thursday night Comedy Central taping.
Although Noah said he was "filled with gratitude for the journey," he also said he wanted to continue exploring "another part of my life."
Before migrating to the US in 2011, Noah started his career in his native South Africa, where he produced a number of stand-up specials and hosted a late-night chat show.
At the conclusion of his program on Thursday, Noah made the surprise, drawing astonished gasps from the studio audience.
He expressed gratitude to the cast and the show's devoted viewers for "an extraordinary seven years," adding, "It's been crazy, genuinely wild."
Many people didn't trust in us when we initially started, he said. "It was a reckless bet to have me serve as host.
His studio audience rose to their feet to applaud him as he concluded his remarks by thanking his viewers.
The comedian told Reuters that he didn't think he would have ever been prepared to follow his iconic predecessor, but that's when you have to do it or you won't be ready.
In addition, Noah said he enjoyed hosting the program because it allowed him to try to find humor even on days with bad news.
The comedian expressed his desire to hit the road once more in order to travel, see new places, and pick up new languages.