Armed with what is reported to be the richest endorsement deal ever for a female athlete, Williams will carry the colors of Reebok International worldwide.
Terms were not announced but the deal was reported to be worth $40 million over five years.
"I won't deny the reports that have been put out there," said Angel Martinez, chief marketing officer for Reebok. "If the reports were far off base, I'd be jumping up and down and would let you know that."
Martinez said the international sportswear giant considered the 20-year-old its biggest star, and a leader of the women's sports movement called the package "an important precedent" for female athletes.
Huge endorsement deals are rare in women's sports. Monica Seles signed a five-year, $25 million deal with Nike after returning to the women's tennis tour in 1996. Martina Hingis has a six-year Nike contract that pays close to $30 million.
Nike also has endorsement agreements with Mia Hamm, Lindsay Davenport, Lisa Leslie and Marion Jones.
Anna Kournikova may have the richest deal of all, a six-year contract with Adidas worth $50 million. But that agreement includes many incentives, including Grand Slam victories and high rankings for a player who has yet to win her first tournament. Its guarantee is about $3 million.
By contrast, Nike has a reported $100 million deal with Tiger Woods, and Michael Jordan generates $40 million a year in endorsement income two years after his retirement.
The Reebok deal thrusts Williams into the higher echelon of endorsement income for female athletes. And like Woods, she has succeeded as a minority athlete in a sport historically dominated by whites.
The impact is expected to be widespread.
"There is no doubt that this endorsement agreement represents the largest such commitment to any female athlete," said Donna Lopiano, executive director of the Women's Sports Foundation. "This is an important precedent for women's sports that announces a new era in the corporate valuing of the female athlete."
David Bober, who represents Hamm, was impressed with the Reebok-Williams contract.
"That's a pretty significant contract for a female athlete," he said. "It can only help shorten the gap between male and female athletes on endorsements. It's another signal that we are moving toward parity, a clear message that women's sports are here to stay."
"The terms are confidential,"> said Williams, who won Wimbledon and the Olympic gold medals as well as the Open this year and is ranked third in the world. "I'll wear Reebok wherever I go. It's a company I believe in. We don't jump on bandwagons."
Neither does Reebok. The company has been affiliated with Williams since she was 11 years old. Their previous agreement, a five-year, $12 million deal signed in 1995, expired in April, just before Williams began a 35-match winning streak that included Wimbledon, the U.S. Open and the gold medal at the Olympics.
Her younger sister, Serena, has an endorsement deal with Puma.
Martinez said Venus Williams remained the company's priority.
"We made a decision there is no better athlete to represent our brand," he said. "When she won tournament after tournament, it added to our excitement."
The 20-year-old Williams recognized the significance of the contract.
"I have to be the best in everything I do," she said. "We've come a long way with the WNBA and the soccer players. I'm doing what I can. Maybe that's the most important part.
"This is a big moment in my life. This is another part of reaching out for my dreams."