In 2009, Windsor's partner of 40 years, Thea Spyer, died after a battle with multiple sclerosis. Spyer left her estate to Windsor, but because their marriage was not legally recognized, Windsor was charged $363,053 in estate taxes.
Windsor first sued the United States in November 2010, arguing that DOMA was unconstitutional. In June 2012, the U.S. District Court for the Southern District of New York ruled in favor of Windsor. The case then went to the Second Circuit Court of Appeals. The panel ruled 2-1 in favor of Windsor.
With the Supreme Court's decision to strike down DOMA with a 5-4 ruling, Windsor will finally be eligible for a tax refund, plus interest.
Windsor heard the news of the court's decision while at her lawyer's home, according to the New Yorker. The room, which was filled with family and friends, erupted in cheers when the news of the ruling came down.
President Obama called Windsor to congratulate her on the victory.
"Hello, who am I talking to?" Windsor said, according to the New Yorker. "Oh, Barack Obama? I wanted to thank you. I think your coming out for us made such a difference throughout the country."
The president also spoke with the plaintiffs in the case against the legality of California's Proposition 8, which banned same-sex marriage in the state.
Former President Bill Clinton, who originally signed DOMA into law in 1996, and former Secretary of State Hillary Clinton released a joint statement applauding the Supreme Court's decision.
"By overturning the Defense of Marriage Act, the court recognized that discrimination towards any group holds us all back in our efforts to form a more perfect union," the statement reads. "We are also encouraged that marriage equality may soon return to California. We applaud the hard work of the advocates who have fought so relentlessly for this day, and congratulate Edie Windsor on her historic victory."
At a New York City press conference following the ruling, Windsor was modest about her role in history and status as an icon in the gay rights movement.
"It's an accident of history that put me here," said Windsor. "If Thea had been Theo," things would have been different, she said.
"What a way to celebrate the life of my beloved Thea," she said.