The Senate approved Lynch’s nomination with a vote of 56 to 43.
After her conformation, President Obama said "America will be better off for it."
He added: "As head of the Justice Department, she will oversee a vast portfolio of cases, including counterterrorism and voting rights; public corruption and white-collar crime; judicial recommendations and policy reviews – all of which matter to the lives of every American, and shape the story of our country."
Sen. Ted Cruz, R-Texas, missed the vote because of scheduling conflicts, including a fundraiser in Dallas, his office said. Cruz, the only absent senator, had voted against Lynch in a procedural vote earlier in the day.
The Senate took more than five months to confirm Lynch after her nomination was mired in political fights. Obama nominated Lynch shortly after Republicans won control of the Senate in the mid-term elections in November and, in a gesture of goodwill, Democrats offered to wait to consider Lynch’s nomination until Republicans took control in January.
Lynch, a North Carolina native who serves as a U.S. Attorney for the Eastern District of New York, will be the first African-American woman to serve as attorney general.
Her confirmation period was the longest of any attorney general nominee in recent history. Two other attorney generals waited longer than Lynch: Edwin Meese, who was confirmed under President Ronald Reagan, waited 386 days, while Mitchell Palmer waited 182 days before confirmation during Woodrow Wilson’s presidency.