Sparks, 17, of Glendale, Ariz., prevailed over beatboxer Blake Lewis, 25, of Bothell, Wash., after a triumphant performance Tuesday that wowed the show's judges and the viewers who gave her a majority of the record 74 million votes cast.
"Mom, Dad, I love you," Sparks, the daughter of retired NFL player Phillippi Sparks, said tearfully after a bearhug from Lewis.
The contest came down to either the stronger singer, Sparks, or the better entertainer, Lewis. Sparks delivered her songs simply and powerfully; Lewis' flourishes included his sound effects and sharp dance moves.
Even the famous were gushing over Sparks.
"She is an awesome singer," finale performer Smokey Robinson said backstage. "She sings so good, it's hard to believe she's 17. To sing like that you would have to have lived for a long time. She's an old soul."
The finale pulled out the stops and the stars, with Gwen Stefani, Tony Bennett, Bette Midler, Green Day and more singing.
The two-hour show opened with Lewis and Sparks dueting on the Beatles "I Saw Her Standing There," followed quickly by a touring Stefani singing "4 in the Morning" via satellite from Massachusetts.
Midler took the stage as the show came toward its close, singing "The Wind Beneath My Wings."
Past "Idol" winners and this season's contestants got a hefty share of attention, starting with first-season winner Kelly Clarkson. She performed her new single "Never Again," with the gritty rock song matched by her black dress and thigh-high boots.
Carrie Underwood, the fourth-season idol, sang "I'll Stand by You" and was honored by legendary music mogul Clive Davis for reaching 6 million in sales for her debut album, "Some Hearts."
Taylor Hicks, last season's winner, also had his moment in the finale sun, as did Ruben Studdard, the winner from year two.
Robinson, a Motown great, performed "Being with You" after the top six male contestants, including fan fave Sanjaya Malakar, sang "Ooh Baby Baby," a hit for Robinson and his group the Miracles.
Blake, whose beat-boxing scored with viewers, performed with veteran rapper Doug E. Fresh on his old hit, "The Show." It was a signature moment for a contest that has introduced young viewers to Gershwin and other standards.
"True originals," host Ryan Seacrest said of the duo.
Gladys Knight took the stage with the six female finalists, belting out "I Feel a Song" and "Midnight Train to Georgia." Bennett performed a mellow version of "For Once in My Life" that ended with a big finish.
"A true idol, Tony Bennett, ladies and gentlemen," Seacrest gushed, with good reason.
Melinda Doolittle, arguably the best "Idol" contestant to miss out on the finale, returned to impress the crowd again as she sang "Hold Up the Line" with gospel stars BeBe and CeCe Winans.
"She has proven in the last few months to be spectacular," BeBe Winans said backstage of Doolittle.
The show took a serious turn when Green Day performed "A Working Class Hero is Something to Be," a single from "Instant Karma: The Campaign to Save Darfur," a fundraising album for the embattled region.
The finale also had its share of filler, including bits such as the "Golden Idols," an award saluting the oddest of odd auditions, or the worst. The winners included Margaret Fowler, who proudly accepted her trophy and recited poetry after smooching Seacrest.
Hundreds of "American Idol" fans lined Hollywood Boulevard leading up to the theater before the show.
"I'm obsessed with the show. I auditioned for it this past season. I'm just coming out to show my love," said Sarah Blackmon, 19, who drove more than two hours from San Diego County to attend the finale.
"I don't like picking favorites. They say it's a music competition, so Jordin's going to win," Blackmon said, but added, "I think Blake's really hot."
One of the series' executive producers, Cecile Frot-Coutaz of FremantleMedia North America Inc., said Tuesday she'd be happy with either contestant as the new idol.
"These are some of the most commercial finalists we've had since Carrie Underwood," Frot-Coutaz said. "Either one will make a great winner for the show and the brand. They both have the potential to sell many records."
For their final performances, both contestants sang "This Is My Now," the tune picked by viewers in an online "American Idol" songwriting contest introduced this season, along with two other songs of their choice.
On Tuesday, judges Simon Cowell and Randy Jackson made their choice clear. Diplomatic Paula Abdul kept her counsel as usual, praising both singers. Although the judges didn't have a say in the decision their opinions have the potential to sway voters.
"You were the best singer tonight. You deserve it all, baby!" Jackson told Sparks.
"You just wiped the floor with Blake," added Cowell, who then told Sparks he was wrong for initially thinking she wasn't good enough to win the Fox talent show.
Before the finale, Cowell spoke warmly of Doolittle and what wasn't to be.
"I'm pleased for the two of them," Cowell said of Sparks and Lewis. "They're nice kids. But I would have liked to have seen one of them up against the big singer."