Though the couple has been living together since 2011 and engaged since 2012, marriage is "different," Theroux told People.
"It does feel different," the 46-year-old actor told the magazine.
"I'm very happy," he added. "It's nice to be able to look down and see a new piece of jewelry on my finger."
The couple wed in a secret ceremony Aug. 5 in their home in Los Angeles.
Asked how she managed to keep the big day a secret, Aniston told ABC News, "Where there is a will, there is a way."
Guests were told they were coming to Theroux’s birthday party, "and it was," Aniston, 46, explained.
The couple recently returned from their honeymoon in Bora Bora.
Back on the Austin, Texas, set of his HBO series, "The Leftovers," Theroux told People the cast and crew "gave me a big cheer so it was wonderful."