When asked by host Ryan Seacrest how he felt, an emotional DeWyze said, "I don't know. It's amazing, thank you, guys, so much ... I love you. Crystal, I love you."
The finalists had closely matched fan bases, with just a 2 percent voting gap between them coming into the finale, Seacrest said. DeWyze's victory was based on votes cast after Tuesday's performance show, which drew more judges' compliments for Bowersox, 24, of Toledo, Ohio, than for DeWyze, also 24, of Mount Prospect, Ill.
The total number of votes cast in the finale weren't announced by Seacrest. That's a departure from most years past: Last season, for example, the high-profile contest between Kris Allen and Adam Lambert drew 100 million phone and text message votes.
Fox didn't comment on the omission. But "Idol," although still TV's top-rated show, has seen audience erosion this season that could have affected the tally. The talented but low-key Bowersox and DeWyze might also have provoked less interest.
Backstage, DeWyze said he was already looking ahead to his next step, which includes making an album and touring. Asked to look back, he said he's learned much from his "American Idol" experience.
"It's OK to put yourself out there and to take risks. Before all this I wasn't always open to big risks like this, and now I'm just like ... I'm going to run with it. And you only live once," DeWyze said.
As for the judges' lukewarm appraisals he got Tuesday, he said it's possible to "nitpick" anything but he's happy with the songs he selected and how he did.
He called Bowersox "amazing" and said, "I love her to death. I know she's going to be successful."
Bowersox was downright Zen about the results.
"I knew Lee was going to win. People seemed surprised by that, but I just had a feeling. I couldn't be happier for him. He deserves every minute of this," she said backstage, looking as calm and cheerful as she has throughout the season.
She viewed the outcome as "winner and non-winner," not winner and loser.
"Both of us are going to have very successful careers and we're going to be friends for a long time," she said of DeWyze.
Before the show, DeWyze was equally philosophical: "Whether I win, which will be amazing, or I came in second, this is a new beginning for me career-wise and in my life," he said.
The finale made the most of Simon Cowell's last appearance as a judge. A film package recounting highlights from the Cowell years was shown and comedian Dane Cook came on stage to sing "Simon Says," made up of the Brit's barbed comments, and to crack a few jokes.
"You have the honesty of Abe Lincoln and the charm of the guy who shot him," Cook told Cowell, who took the ribbing with a smile.
The walk down memory lane continued with ex-judge Paula Abdul, who often played Cowell's sparring partner during the seasons the shared.
"I've loved all the fun we've had together," Abdul told Cowell. "`American Idol's' not gonna be the same without you. But as only I can tell you, it will go on."
Cowell, in turn, shed his usual cool in an on-stage appearance.
"I didn't think I was going to be this emotional and I genuinely am. ... Everybody asks who's going to replace me, who going to be the next judge. The truth is," he told the audience, "you guys are the judge of this show and you've done an incredible job over the years."
The finale, as usual, was stuffed with humor, including the return of Larry "Pants on the Ground" Platt and William Hung, return appearances by former contestants and music stars.
Kris Allen, last year's winner, sang "The Truth," with Carrie Underwood, Michael McDonald, Christina Aguilera, Hall & Oates, Robin and Barry Gibb, Janet Jackson and Joe Cocker were among those whose performances were scattered throughout the two-hour show.
Bret Michaels, the ailing former Poison frontman and reality TV star, joined "Idol" finalist Casey James on one of the band's biggest hits, "Every Rose Has Its Thorn."
David Cook, a past "Idol" winner, was unable to attend because of a charity commitment, Fox said.
Bowersox, with a distinctive, Janis Joplinesque-voice and whose status as a single mom and warmth earned her the nickname "Mama Sox," had basked in praise Tuesday.
"You took that song and you absolutely nailed it," Cowell said of Bowersox's rendition of "Black Velvet," a song he said he's normally "allergic" to because it gets murdered.
The assessments of DeWyze were respectful but more measured -- with Ellen DeGeneres the exception.
"Lee, I couldn't be prouder if I birthed you myself," she told him after he sang Simon and Garfunkel's "The Boxer."
DioGuardi admired DeWyze as an "emotionally accessible" singer after he performed R.E.M.'s "Everybody Hurts" as his second number, but Cowell urged him to try harder.
"When you come out for your last performance, I want a 10 out of 10, because you're capable of that," Cowell told him.
With U2's "Beautiful Day," Jackson welcomed hearing "the guy with the strong big rock voice" and DioGuardi said he had "one of the most commercial voices of the season" and deserved to be in the finale.
Cowell, who had pointed to DeWyze as the frontrunner before the finale performances, said that "American Idol" was designed for someone like DeWyze, who worked in a paint shop when he tried out for the show and needed a break.
DeWyze's first single will be "Beautiful Day," which he performed Tuesday.
Seacrest, who appeared to have an on-air testy relationship with Cowell this season, had only warm words for him Tuesday and Wednesday.
"We really are going to miss you. You are a dear friend and we wouldn't be here without you," Seacrest said.
Cowell isn't going far: He's going to produce and judge "The X Factor," a Fox version of his popular British talent contest.