"I'm absolutely positive she is the right person for the moment," Obama said, praising Wasserman Schultz as someone who "embodies the core values we cherish as Democrats and Americans."
The president predicted "a tough 18 more months," but said "I'm confident we're gonna get this done."
The four-term lawmaker will head the committee during Obama's reelection bid and while Democrats try to win back control of the House and maintain control of the Senate.
Wasserman Schultz heralded her election as a milestone for women and pledged to fight Republican efforts to "undo" Democratic accomplishments.
"On my watch, we will not be outworked," she said.
She pledged to "call out" Republicans who attempt to "undo or distort" major Democratic legislative victories like healthcare reform and Wall Street reform.
She also pledged to further Obama's formidable grassroots organization ahead of 2012, touting the 50-state strategy of former DNC Chairman Howard Dean.
"Support for the 50 state strategy, our candidates and our committees will be among my highest priorities," she said.
The vote to elect Wasserman Schultz was preceded by a fiery speech from interim DNC Chairwoman Donna Brazile, who praised Wasserman Schultz as a "warrior" and hit back at critics who have questioned how Wasserman Schultz will juggle the dual roles of lawmaker and national party chairwoman.
"For those who ask, 'How can she multitask?'" said Brazile. "I say, 'Get with it.'"
Quoting rocker Tom Petty, Brazile said she's confident Wasserman Schultz "won't back down," even in the face of Republicans who seek to "take the next presidential election."
Sixty-three DNC members were present at the Wednesday meeting, with another 196 committee members joining the gathering by phone.
Wasserman Schultz has built a reputation among national Democrats as a prolific fundraiser who can boast close relationships with top donors across the country.
In keeping her House seat, Wasserman Schultz will be the most direct conduit between Obama and House Democrats — a relationship that's had its fair share of ups and downs over the past two-and-a-half years.
The Republican National Committee welcomed Wasserman Schultz's election with a statement warning the new chairwoman that she "has her work cut out for her."
"With millions of Americans still looking for jobs, four dollar a gallon gas, rising consumer good prices and efforts by Democrats to give Barack ObamaBarack ObamaNorth Korea is a problem, but China and Pakistan are just as harmful 21 state AGs denounce DeVos for ending student loan reform Trump’s wall jams GOP in shutdown talks MORE a blank check to raise Washington's spending, she certainly has her work cut out for her," RNC spokeswoman Kirsten Kukowski said.