August 31 was International Day for People of African Descent, and one woman in particular stands out among African Americans who have changed the world: Serena Williams. The glamorous American tennis player not only revolutionized women’s tennis with her powerful game style, but she has been a powerful advocate for black people both on and off the court during her almost 30-year career in professional tennis. She has announced she will retire from tennis but will remain an activist for equality and racial justice.

Williams holds the record of having won more Grand Slam singles titles than any other woman —or man, for that matter— during the US open. Born in 1981, in Saginaw, Michigan, USA, Williams and her older sister Venus grew up in Compton, California. Their parents encouraged the two sisters to play tennis, and with the help of their strict coach Richard Williams and long hours of practicing, they soon attracted attention for their powerful serves and superb athleticism.

Serena became the first Williams sister to win a Grand Slam singles title, in the 1999 U.S. Open. At that tournament the sisters won the doubles event, and, over the course of their careers, the two teamed up to win 14 Grand Slam doubles titles.

Just a few of the highlights of their careers show what incredible accomplishments these two women of African descent achieved. At the 2000 Olympic Games in Sydney, Australia, Serena and Venus won gold medals in the doubles event. They won their second doubles tennis gold medal at the 2008 Olympic Games in Beijing. Later that year, Serena won the U.S. Open for a third time. In 2009 she captured her 10th Grand Slam singles title by winning the Australian Open. Later that year she won her third Wimbledon singles title, once again defeating her sister. Williams defended her titles at the Australian Open and Wimbledon in 2010.

In 2012, Serena captured her fifth Wimbledon singles title. A month later at the London Olympic Games, she won a gold medal in the singles event, becoming only the second woman to win a career Golden Slam. She also teamed with her sister to win the doubles event. Later that year Serena claimed her 15th Grand Slam singles title with a victory at the U.S. Open. In 2013 she won her second French Open singles championship and fifth U.S. Open singles title. Williams successfully defended her U.S. Open championship in 2014, which gave her 18 career Grand Slam titles.

The following year Serena captured her sixth Australian Open. She then won the 2015 French Open—her 20th total Grand Slam singles championship. She continued her success at Wimbledon, winning a straight-set final to capture her sixth career Wimbledon singles title. Serena again won Wimbledon in 2016, giving her 22 career Grand Slam singles titles. Serena broke Graf’s record at the 2017 Australian Open, defeating her sister in the final.

But success didn’t come easy to Williams. She has battled health issues that kept her off the court for nearly a year. She has been criticized for everything from her curves, to her hair and clothing. Yet throughout it all, she has confronted racism, misogyny, and double standards in the sport.

Her trademark was bold outfits that highlighted her strength and challenged traditional — and typically conservative — dress codes. She garnered criticism and was banned from the 2018 French Open for wearing a skintight catsuit that she said was designed to help her blood circulate to prevent blood clots.

She has always celebrated the skin she’s in. “I think my mom instilled in us to be confident women, to really believe in ourselves, be proud of our heritage, our hair and our bodies,” she told Essence in an interview.

She has also confronted double standards on the court. When Williams returned to tennis in March 2018 after the birth of her daughter, she failed to win a tournament that year, though she reached the finals at both Wimbledon and the U.S. Open. The loss proved controversial when she was penalized one game after arguing with the chair umpire over a code violation. Her insistence on an apology from umpire Carlos Ramos resulted in a fine and criticism for her response to his calls. She was fined $17,000 for disputing her penalties.

Since then she’s spoken out about the unfair treatment and expectations many Black women face. “Funny how a Black female tennis player is held to a higher standard to keep her emotions in check than a Supreme Court nominee,” Williams told GQ in November of 2018, referring to the temper tantrum indulged in during a Senate confirmation hearing by then-Judge Brett Kavanagh.

In 2019, she was again defeated in the finals at both Wimbledon and the U.S. Open. At the 2020 ASB Classic in Auckland, New Zealand, Serena won her first singles event in some three years.

In 2021, she was forced to withdraw from both Wimbledon and the U.S. Open because of injuries. After missing the first half of the 2022 season, Williams competed at Wimbledon this past June but was defeated in the first round.

Williams subsequently revealed that she would be retiring after this year’s U.S. Open in an interview with Vogue magazine. Williams stated that she is “evolving away from tennis, toward other things that are important to me.”

For example, Serena championed the UNICEF Schools for Africa initiative, providing education to the most marginalized and vulnerable children. Appointed a Goodwill Ambassador in 2011, she supported the #EveryChildAlive campaign by advocating for affordable, quality health care for every mother and newborn.

On the court, Williams not only redefined gender roles in sport, but expanded conceptions of the working mother. Her daughter, Olympia, became a fixture on tour while her husband, Alexis Ohanian, Reddit’s co-founder and former executive chairman, took parental leave.

Off the court, she pursued ventures relating to fashion, beauty, and accessories. Taking on racism and sexism, she was always ready for a fight, both on and off the court. Famous for saying before Wimbledon: “The day I stop fighting for equality will be the day I’m in my grave,” she leaves a legacy of advocacy that has already inspired up and coming young athletes.

“Williams seemed like a superwoman,” wrote Donovan Bennett, a radio host on Sportsnet. “But her true power wasn't her utter on-court dominance. It was forcing us to change our minds, to rethink our biases, by confronting realities.”