Tejay van Garderen added the USA Pro Challenge title to the Tour of California crown he won in May on Sunday, as Slovakia's Peter Sagan claimed the final stage.
"I felt like it was a long time coming because I've been so close both the other times," said van Garderen. "It's amazing to get it."
The 2013 Tour de France sprint jersey champion Sagan notched his fourth stage win in the seven-stage event as the Cannondale rider's sharp bust at the finish gave him the win in the 116.5 km circuit race in the streets of Denver in two hours, 27 minutes, 15 seconds.
He edged Canadian Ryan Anderson, with United HealthCare's Alessandro Bazzana of Italy a close third.
American BMC rider van Garderen led the sprint out into the final 300 metres. He placed 15th to secure the victory.
His Swiss teammate Mathias Frank was second overall 1:30 behind and American Tom Danielson (Garmin Sharp) completed the podium.
Sunday's final stage took the riders on eight laps of a tight city circuit.
Seven riders broke away in the first lap and the aggressive pace seemed to take its toll on Tour de France champion Chris Froome, who was 94th going into the final stage. The British Sky rider abandoned the race on the second lap.
The gap was at one minute with 78km to go, but thanks largely to pressure from Cannondale the leaders were caught within the final kilometre.
Van Garderen, who had taken the overall lead in the fourth stage on Thursday, was delighted to have held on for the win after previous second- and third-place finishes.
"Other years, I maybe wanted it too bad," he said.
