But this past December, the world discovered that Thurmond, one of the country's most powerful and controversial senators, had secretly fathered a black daughter.
Thurmond, who died last summer at 100, was a lightning rod for American racial politics.
In an interview with Correspondent Dan Rather last winter, Essie Mae Washington-Williams gracefully stepped into history as yet another symbol of this country's complicated relationship with race.
In the months since, her story has been publicly debated and revered. A commemorative coin is being issued in her honor, and numerous speaking engagements, book and television deals are in the works.
Williams has also met privately with some members of the Thurmond family at the home of Strom Thurmond Jr., her younger half-brother. It was a quiet closure to a story that was most of a century in the making.
Thurmond never publically acknowledged his oldest daughter, or the active role he played in her life.
But last winter, Williams finally shared her long-secret tale of a family and a country divided by color.
"For 50 or 60 years now, this thing has been following me. So the fact that I am coming out now to talk about it is like a burden being lifted, because I had this secret," says Williams, who told Rather her secret on the eve before telling the rest of the country.
"And though many people did know about it, I hadn't gotten it off my shoulders. So this is what I wanted."
Williams, 78, and her family prayed before her South Carolina news conference last December, where she faced a roomful of cameras and the questions she had avoided for decades. She was not joined by the other Thurmond children, who said they accepted her claim, but preferred to meet her privately.
However, Williams says she knew who she was all along; it just took the rest of the country a while to catch up: "I met my father in 1941, when I went to South Carolina. I was about 16 years old. At that time, my mother had taken me over to see him and introduced us to each other. And since that time, I was in contact with him constantly."
"She did not mention anything about his color," adds Williams. "And when I met him, I was surprised because she'd never mentioned that he was white."
Her mother was a 16-year-old domestic in the home of Thurmond's powerful and wealthy father. He was a 22-year-old teacher and track coach at the local school.
Did her mother care for him? "Well, she thought he was a very nice person. And basically, he is, or was, a very nice person," says Williams.
Did Thurmond ever deny at any time that Williams was his child? "The first time he saw me, he said, 'Well, you look like one of my sisters. You've got those cheekbones like our family,' so that was almost an admission … without saying … yes, you are my daughter," recalls Williams. "No, he never said anything negative about that."
But if he was a tender father in private, the rest of the country saw a tougher side, an angry side, when it came to race.
Back then, segregation was the law of the south, and Thurmond was one of its most vocal proponents. That paid off big for him politically. He went from a state senator to governor to segregationist presidential candidate. And in some minds, this forever sealed his reputation as a race-baiting bigot.
His daughter, however, saw him differently: "Whenever I came in, he would always hug me when I came in. And when I'd leave, he'd hug me. But he never came out and said, 'I love you',' but he sort of showed it in his expression."
Williams says she loved her father: "It felt good that at least my father cared something about me. It made me feel better."
But his pronouncements on race stung at times during political discussions. "I did question him when I was in college. Why was he a racist, a segregationist at that time, and he said, 'Well that's the way things have always been,'" recalls Williams. "And I said 'But, you know, you're in a position maybe you could do something' and he said he was doing as much as he could at the time."
In her mind and heart, did she think he was a racist? "I don't know that at heart he was. I think he did what he did to promote his career, but I never heard him using any negative words or maybe statements about black people in general. He never did that," says Williams. "I don't believe he was a racist at heart. And when the times changed, he changed."
Thurmond paid his daughter's college tuition when she attended South Carolina State College, an all black university. Then governor, Thurmond created a sensation when he visited her on campus. But still, she stayed silent.
"It wasn't to my advantage to talk about anything that he had done. It certainly wasn't to either one of us. And he, of course, didn't want it to be known. Neither did I. I didn't want it to be known either," says Williams, who knew that speaking out would have ruined Thurmond politically. "Oh, yes, and I would not have wanted to do that."
So she and her father kept their secret to themselves, and went on with their separate lives as the nation fought over civil rights, and eventually changed course.
Thurmond and his secret daughter stayed close, meeting regularly and exchanging cards and letters, like the one he sent thanking her for a Father's Day card. He also consistently helped her financially, and paid for her visits to Washington and back home.
But as they both grew older, things changed. "He said 'You shouldn't have to make these long trips. I can just get a check and send it to you.' So he started sending checks. Up until then, it was always cash because they didn't want a record of it," says Williams, who wouldn't comment on the amount of money he gave her. "The amount that I did receive helped me quite a bit. But I don't wanna go into figures."
The money dwindled when Williams married, but the visits continued. Once, she brought along a surprise when she came to see Thurmond – her first son. "We went to visit him and that was the first time he'd seen his first grandchild," says Williams. "He thought he was a beautiful baby."
Williams became a school teacher, and lived a quiet life in California, while Thurmond stormed the national stage in a battle over civil rights. His financial support of his daughter and her four children took a significant leap after Williams' husband died.
"He knew that my husband had passed, because we kept in touch, and we talked and he decided he would continue helping me with the children until they were all grown up. And he did that," says Williams.
By the time he was recognized as the country's oldest senator, he was a secret grandfather to four successful black adults. With the help of his money, and her mothering, Williams raised a doctor, a transit operator, a social worker and a computer entrepreneur.
Wanda Terry is Williams' oldest daughter. She first met her grandfather when she was 16.
"He walked over to us, and he had the opportunity to shake my hand, along with my brothers and sisters. And he said, 'You have a nice looking family' to my mother," recalls Wanda. "I just thought it was nice to meet him. I didn't think anymore about it."
She met him again a second time last year in Washington, D.C. This time, she says, he told her, "You look just like your mom."
It was a poignant relationship -- a father and daughter, proud of each other, but both aware that going public would destroy his career and her privacy. But she watched from a distance as her father married twice and fathered four more children, and became a grandfather -- this time in public.
Like many with strong opinions about Sen. Thurmond, Frank Wheaton, the Williams' family attorney, has said that Essie Mae's story has changed his feelings.
"The humanity. The human being behind Strom Thurmond. I certainly had every perception, every illustration of this man, who by definition, was a racist, was a bigot. And then when I learned more about her relationship with her father," says Wheaton. "It was above all else a parent-child relationship, a father-daughter relationship. They never spoke about his profession or his job. They only really spoke about what she needed in him as a father and his love for her as a daughter."
She kept her secret for 62 years, and now, she's celebrating her moment of truth. She's not just rewriting history, she's gently setting the record straight about just who is welcoming whom to the family.
Recently, the family of the late Sen. Strom Thurmond acknowledged that Williams is his illegitimate daughter.
"Oh, they wanna welcome me to the family now," says Williams. "It's nice to hear it. But Nancy, his wife and her children, they were nowhere around when I was born. And I had this relationship with him that was very good. So when they made the announcement, it didn't have any great effect on me … because I was there before they were."
Just this month, the governor of South Carolina decided to add Williams' name, along with Thurmond's other children, to the Thurmond monument on the statehouse grounds.
And Williams says she will now seek membership in the United Daughters of the Confederacy.