The 10-year-old suit has taken on at least some of the trappings of a Gideon v. Wainwright or a Brown v. Board of Education, where people of humble origins used the courts to force change on powerful institutions.
Dukes, 61, witnessed the hour-long oral arguments in Washington.
"Seeing those nine judges sitting on the bench was something to behold," she said. "You never know where life is going to take you."
Last week, Dukes was again organizing shopping carts and chatting with customers as a greeter at the Wal-Mart on Loveridge Road, where she has worked for 17 years.
She said things had settled down at work in the years since she filed the suit.
"Our managers now weren't even working for Wal-Mart when the suit was filed," she said.
The woman behind the lawsuit started as a part-time cashier with the Pittsburg store in 1994.
She became a full-time cashier a few months later, then was promoted to customer-service manager in 1997.
Dukes said she noticed a pattern in which men were trained for the jobs she wanted while women were often ignored. She said she later learned that a male coworker was making 50 cents per hour more than she was for doing the same job, even though he had worked at Wal-Mart for a much shorter time.
Her unhappiness with some of the Pittsburg store's managers boiled over in 1999, when she filed a complaint against them after she was demoted to cashier.
"I felt that I was victimized, and I started up the chain of command with upper management to no avail," Dukes said.
She said that she called attorneys who specialize in labor issues but that many backed off when she mentioned Wal-Mart, telling her a suit against a company that big would be too expensive.
She eventually was referred to her lead attorney, Brad Seligman.
"She has hung in there for many, many years and done it under the extraordinary circumstances of working for the company she is suing," Seligman said.
Wal-Mart has vigorously denied any companywide discrimination practices and argued to the high court that Dukes' suit should not be granted class-action status because it would force the company to defend the treatment of female employees regardless of the jobs they hold or where they work.
If the justices rule against the class action, attorneys will still take Dukes' case to trial, Seligman said.
Despite the acrimony that led to the suit, Dukes said she had always enjoyed working at Wal-Mart.
She said she would be happy when the litigation was over.
"When we first filed the suit, I thought it might go on for seven years and [Wal-Mart] would settle," she said. "We didn't take Wal-Mart to the Supreme Court; they took us."