But the normally acerbic X Factor judge choked up Wednesday night as he introduced the show's emotional tribute to the Sandy Hook shooting victims – in what he later said was an extremely difficult moment for him.
"I would say it was the hardest thing I've ever had to do on TV in my life," Cowell, 53, said after the show, in which Carly Rose Sonenclar, Tate Stevens and Fifth Harmony made their final performances of the season.
"We made the decision and decided that we were going to introduce it like we did," said Cowell. "And then it hits you what you are about to announce and what it is about."
He added: "I think anybody in my position would have been the same, and I think it was much harder for the singers. For them to have to sing that lyric … it was a miracle they did it, because it really affected them. But it was the right thing to do."
The show opened on Cowell sitting alone. "Words cannot describe what happened at Sandy Hook Elementary School last week," he said. "We're all deeply saddened by the tragedy, and our hearts right now go out to the families. You'll always be in our prayers, and you'll always be in our hearts, and this is our tribute to you."
Various contestants who'd been eliminated then gathered on the stage, all dressed in white, and sang Michael Jackson's "You Are Not Alone."
On a lighter note, Cowell addressed the issue of L.A. Reid leaving the show, and said he hasn't thought about a replacement yet.
"It would be crazy to think about it while the show is on," he said. "Take a couple of weeks off, regroup, and sometimes I'll wait for the calls to come in. I prefer that."
Asked whether Britney Spears and Demi Lovato will be back, he replied: "I've got to ask them first of all. Maybe no one wants to come back!"
The winner of The X Factor's second season will be revealed Thursday night on Fox at 8/7c.