An 83-year-old widow will carry the hopes of America's gay community on her frail shoulders when she takes her landmark same-sex marriage case before the US Supreme Court next week.

Edie Windsor, a lesbian who married in Canada, is seeking to overturn the federal Defense of Marriage Act, which has defined marriage as a union "between one man and one woman" since it became law in 1996.

Windsor is challenging DOMA on the basis that it discriminates against same-sex couples, noting that Section 3 of the law denies gay and lesbian couples the same rights enjoyed by married heterosexuals.

The former IBM executive was forced to pay $363,000 in federal inheritance taxes when her partner of more than 40 years, Thea Spyer, died in 2009 -- money she would not have had to pay if she'd been married to a man.

One of the elderly plaintiff's lawyers, James Esseks, described the determined octogenarian, who has a recent history of heart problems, as a hero of the fight for same-sex marriage.

"Edie is a rock star in my world, and she's getting an increasing recognition within the gay and lesbian community because she's been so brave to put the details of her personal life to the public inspection to be judged, also because of the strength of character that she brought in her relationship," Esseks said. "She's my hero.

"She's quite a character, a wonderful story... she wants to be married like everybody wants to get married."

In a 62-page brief to the Supreme Court, Windsor lays out the details of a moving personal journey that began when she fell in love with Spyer in the early 1960s.

This, she says, was an era "when lesbians and gay men risked losing their families, friends and livelihoods if their sexual orientation became known."

After a brief union with a man -- "because she did not believe that it was possible for her to live openly as a lesbian" -- while she worked as a computer programmer for the US Atomic Energy Commission, she began her relationship with Spyer in 1965. The pair had first met two years earlier.

The relationship lasted 44 years. The two New Yorkers married in Toronto, Canada in 2007, when Edie was 77. New York did not legalize same-sex marriage until 2011.

However, two years after tying the knot, Spyer died from multiple sclerosis -- leaving Edith facing hefty taxes to inherit the couple's apartment, because US federal law did not recognize their Canadian marriage.

"She wouldn't have had to pay if she had been a straight widow instead of a gay widow," Esseks said.

"We have here a couple that has been together for four decades, that has helped each other through very serious illness and sickness, as we say in the marriage vows."

President Barack Obama's administration had opposed Windsor's bid to repeal Section 3 as it progressed through the lower courts, where the legislation was twice ruled as unconstitutional.

But the White House has since switched sides and is now calling for the law to be overturned, leaving DOMA to be defended by a group of Republican lawmakers, along with a coalition of religious and conservative groups.

Windsor said she will be thinking of her late spouse when her Supreme Court hearing gets underway, noting the scenario was unthinkable when the couple first met in the 1960s.

"I think she'd be so proud and happy and just so pleased at how far we have come," Windsor said.

"It's a culmination of an engagement that happened between us in 1967 when we didn't dream that we'd be able to marry."