Josh Kaufman, 38, of Indianapolis triumphed in the viewer vote over two other singers who made it to the two-hour finale of the NBC singing competition: Christina Grimmie, 20, of Marlton, N.J., and Jake Worthington, 18, of La Porte, Texas. Worthington finished second.
Kaufman, a member of Team Usher, is an SAT tutor and married father of three. It was Usher's first coaching victory, breaking a string of wins by coaches Adam Levine and Blake Shelton since the series began.
Kaufman's family joined him on stage as the show ended. "I can't even talk," he told host Carson Daly just after his victory was announced. "I'm overwhelmed, surprised, happy, relieved."
The Emmy-winning show tossed out some votes tallied by downloads because of a glitch involving Kaufman's song, but Daly said it did not change the overall outcome.
Levine and Shelton, who have been on every edition of The Voice, will be back for Season 7 in the fall with newcomers Gwen Stefani and Pharrell Williams. They said a temporary goodbye Tuesday to Season 6 panelists Shakira and Usher.
Moments after the show, Kaufman described his feelings leading up to the winner announcement.
"It had been such a stressful night and morning, a lot of nerves and heart racing and waiting ... It felt like forever," he told reporters at a news conference. "It was mostly just anticipation and wondering what was going to happen next."
He described his early thoughts on the type of album he would make. "At the root of everything I do is a kind of soulfulness," Kaufman said. "You can add a pop element, you can add rock into that. ... I want to find a balance between something that's classic and something that's modern."
Usher said the win provides an incentive to return as a coach.
"This is definitely a great way to close Season 6. It obviously gives a great reason and logic to come back and defend the title, but more than that, to change the idea of what type of winner and what it takes to win, the type of songs you choose," he said. "Josh put up an incredible performance and fight. ... He's a shining example of what you can do if you have determination, passion and commitment."
Usher initially declined to gloat in his victory, which ended a string of five by Levine and Shelton since the show began. He called them "amazing coaches" and even praised what some considered Adam's slip, letting Usher steal Kaufman from his team earlier in the season. "I wouldn't have found a way toward a win without Adam recognizing Josh's talent."
Goaded by Daly, Usher then shifted gears. "Man, it feels good to have another coach win. I couldn't take another season of that," said the performer, who first coached in Season 4.
Later, in a separate news conference, three-time coaching champ Shelton complimented Usher.
"I think viewers of the show were ready for somebody else to win. You've got to change it up at some point," he said. "To be honest with you, when I heard Usher was coming to the show for Season 4, I thought at that point, 'It was fun for a minute.' Just knowing his history with developing artists, the fact he worked with (Justin) Bieber, obvious things like that, I just thought, 'We're never going to win again.' And then the fact we did was a shock to me. If there was ever anyone I thought could beat us, that would be Usher."
Shelton paused, changing tone. "That ain't never gonna happen again."
OneRepublic opened Tuesday's splashy finale. Other performers included Coldplay, Tim McGraw and Ed Sheeran. Sheeran also sang with Grimmie, Kaufman did a duet with Robin Thicke and Worthington performed with Alabama.