NBC declared Shumlin, the state Senate's president pro tempore, the winner after he narrowly edged the lieutenant governor in Tuesday's election. Shumlin will succeed Republican Gov. Jim Douglas, who is retiring.
Vermont is one of two U.S. states where the governor serves a two-year term. The other state is neighboring New Hampshire.
Shumlin said he was "humbled" and "honored" by the victory, WCAX-TV, Burlington, reported.
"I have worked hard all my life to get tough things done, we have tough things to do, and today we begin that for every single Vermonter, every single day, to make your future better, that struggle starts today," Shumlin said.
Shumlin said Dubie was gracious when the lieutenant governor called to concede.
"I was his friend before this campaign, we'll be friends going forward," Shumlin said.