(CNN) -

Over the course of her remarkable life, Althea Gibson was many things to many people -- an accomplished jazz singer, a saxophone player, an actress and the first black woman to play on the professional golf circuit.

For Billie Jean King and tennis fans around the globe, however, Gibson will always be best remembered as a towering figure of their sport. And not just because of her imposing stature.

"I saw Althea Gibson play (tennis) for the first time when I was 13. Because she was already one of my 'she-roes' I was very excited" says King, who herself won 12 grand slam singles titles as well as founding the Women's Tennis Association.

"Her story is quite unexpected and quite wonderful at the same time," she told CNN's Open Court show.

Gibson won an impressive 11 grand slam crowns (five singles, five doubles and one mixed doubles) between 1956 and 1958.

"She was so exciting to watch," King says. "She was almost six feet and she had long arms, long legs -- very intimidating to the other players, you could tell."

While King herself is rightly lauded as one of the all-time tennis greats, the achievements of her idol Gibson are often overlooked.

Perhaps this is to do with fading memories, the inaccessibility of the grainy black-and-white footage that recorded her in action, or the fact that tennis remained an amateur sport during Gibson's playing days.

For tennis historians, however, her legacy remains an important part of the sport's history.

Gibson inspired prominent black players including three-time men's grand slam winner Arthur Ashe, 1990 women's Wimbledon finalist Zina Garrison and modern day greats like the Williams sisters. Venus Williams once said she had all the opportunities she has today "because of people like Althea."

For Gibson to achieve what she did, however, she had to scrap, battle and overcome barriers that few of her contemporaries would have been faced with.

Forgotten legend

Born in South Carolina in 1927 before being raised in New York's tough Harlem district, Gibson spent much of her youth playing ping-pong or practicing on local tennis courts.

Aware of her special talent, the tight-knit Harlem community raised funds to help pay for coaching lessons.

According to friend David Dinkins, former mayor of New York City, her ability was obvious from a young age.

"(She) learned her tennis much like Billie Jean King, just hitting against walls and she was pretty damn good," Dinkins says. "She was tall and she had a good serve/volley ... she was tough."

She had to be. America in the late 1940s and early '50s was a very different place than it is today. The dark specter of racial segregation still hung over many parts of the country.

"It was American apartheid, like South Africa," Dinkins says. "But that's the way we were. Most tennis was played at country clubs and places that didn't admit people of color, so it was tough for her."

But the young Gibson was nothing if not resilient.

With the backing of family, friends and the American Tennis Association Junior Development Program -- an organization that identified and helped talented young African-American players -- she graduated high school before being admitted to Florida A&M University on a full athletic scholarship in 1949.

"She had a community that really loved her and made a huge difference in her life," King says.

"These people really were there for Althea, as a person. You don't have to have the whole world behind you but if you have a nucleus of friends who care, I think that's probably what got her though it."

Gibson would also find she had advocates within the game as she progressed from playing in local and regional tournaments.

An impassioned appeal from 18-time grand slam winner Alice Marble is widely credited with ensuring Gibson became the first black player to receive an invitation to appear at the United States National Championships (the forerunner to the U.S. Open) in 1953.

"If tennis is a game for ladies and gentlemen ... it's time we acted a little more like gentle-people and less like sanctimonious hypocrites," Marble wrote in American Lawn Tennis magazine.