Stewart had been off Comedy Central since June 6, directing and producing a movie. John Oliver subbed to strong reviews.
He was welcomed in an extended skit with Oliver and Stephen Colbert, who tried to bring back the old Stewart after Oliver mock-worried that "the Middle East has changed him."
Back at his desk, Stewart beckoned the camera close to whisper to his audience: "I've missed you so much. You don't know what it's like in the real world. Nobody applauds every stupid (expletive) thing that you do."
Stewart played a tape of President Barack Obama urging military action against Syria because of last month's poison gas attack.
"America taking military action against a Middle East regime," Stewart said. "It's like I never left."
After showing Secretary of State John Kerry refer to "signatures of sarin gas" in the attack, Stewart launched into a mock commercial for "Signature of Sarin" perfume.
"I came back to a dark, dark place," he said.
He played news network tape of various pundits saying that military action against Syria is necessary because the United States would look weak without doing it.
"Oh, right," he said. "We have to bomb Syria because we're in the seventh grade."
There were no actors pushing projects for Stewart's first guest during his return. He conducted an interview with the head of the United Nation's relief effort in Jordan, taking care of refugees from Syria that have now exceeded two million.