Lilly Ledbetter, a women’s equality activist whose fight for pay equity led to passage of the monumental Lilly Ledbetter Fair Pay Act of 2009, died Saturday. She was 86.

Ledbetter’s death was confirmed on Monday by Jodi Solomon, her speaking manager.

“She was fierce, she was a crusader and just a really good friend. She will be missed a lot,” Solomon told NPR.

Born in Jacksonville, Ala., Ledbetter was hired as a supervisor at a Goodyear tire plant in Gadsden, Ala., in 1979. Years later, she discovered through an anonymous note left in her mailbox that she was receiving less pay than her male co-workers who worked the same position.

“When I saw that, it took my breath away. I felt humiliated. I felt degraded,” Ledbetter recalled in an interview with NPR in 2009. “I had to sort of get my composure back to go ahead to perform my job and then, the first day off, I went to Birmingham, Ala., and filed a charge with the EEOC.”

That action in 1998 was the beginning of a 10-year legal fight for Ledbetter toward equity.

She retired from Goodyear 11 months after she found out about the pay disparity and filed a gender discrimination lawsuit against the company in 1999. She won the suit in 2003 and was awarded more than $3 million, but the amount was reduced to $300,000 because of a statutory cap and $60,000 in back pay. Goodyear appealed the decision to the Supreme Court, arguing that Ledbetter could only win damages or back pay for the 180 days prior to the filing of her claim. In 2007, the high court agreed in a 5-4 ruling.

In her dissent, Justice Ruth Bader Ginsburg said Ledbetter’s case is “not time barred” and wrote the issue “is in Congress’ court.”

Less than two years later, Congress passed the Lilly Ledbetter Fair Pay Act of 2009, which amended the Civil Rights Act of 1964 and allows workers to “obtain relief, including recovery of back pay, for up to two years preceding the filing of the charge.” Then-President Barack Obama signed the measure into law on Jan. 29, 2009, the first bill he signed as president.

Obama paid a tribute to Ledbetter in a statement on Sunday.

“Lilly Ledbetter never set out to be a trailblazer or a household name. She just wanted to be paid the same as a man for her hard work,” he wrote. “Lilly did what so many Americans before her have done: setting her sights high for herself and even higher for her children and grandchildren. Michelle and I are grateful for her advocacy and her friendship, and we send our love and prayers to her family and everyone who is continuing the fight that she began.”

Ledbetter has been recognized for her advocacy on pay equity and her story continues to resonate.

Last week, Ledbetter was honored with a Lifetime Achievement Award from Advertising Week for her activism on Equal Pay. Lilly, a movie based on Ledbetter’s life, is being shown at screenings across the country.

NPR’s Nina Totenberg contributed to this report.