David Cook, a sometimes sullen 25-year-old rocker from Blue Springs, Mo., was named the winner of "American Idol" on Wednesday, receiving 56 percent of the 97.5 million votes cast after Tuesday's performances, easily winning over David Archuleta, a 17-year-old balladeer from Murray, Utah.

It was in many ways a surprise victory. During Tuesday's competition, all three of the program's judges seemed to endorse Mr. Archuleta as the winner. To many observers in the 7,000-seat Nokia Theater here, Mr. Archuleta's final performances were the more electric. Simon Cowell, the sometimes-petulant judge who rarely is at a loss for words, seemed to speak for the other judges at the end of Tuesday's show when he said that Mr. Archuleta "came out here to win" and did so by "a knockout."

But Mr. Cowell, who months ago predicted that Mr. Archuleta was the contestant to beat, presaged the results minutes before the winner was announced on Wednesday, apologizing to Mr. Cook and saying that his remarks on Tuesday were "verging on disrespectful."

Fox rode the Idol juggernaut to yet another ratings victory in the current television season. The show's average audience of more than 25 million viewers is more than one-third larger than the next most popular show on broadcast television, ABC's "Dancing With the Stars."