Story highlights Essie Mae Washington-Williams kept her father's identity secret until his death

"I never wanted to do anything to harm him," she said

Thurmond fathered the child with a teenage black housekeeper in 1925, family lawyer confirmed

Thurmond ran for president in 1948 on a segregationist platform

Essie Mae Washington-Williams, the biracial woman who revealed nine years ago she was the illegitimate daughter of former segregationist Sen. Strom Thurmond, died Monday, her family's spokesman said. She was 87.

Washington-Williams kept her father's identity secret until six months after Thurmond, a segregationist leader for decades, died in June 2003 at age 100.

"I never wanted to do anything to harm him or cause detriment to his life or to the lives of those around him," Washington-Williams said at a 2003 news conference, six months after her father died at the age of 100.

She died at her Columbia, South Carolina, home of natural causes Monday morning, according to Frank Wheaton.

Thurmond ran for president in 1948 on the ticket of the States' Rights Democratic Party, or Dixiecrats, a breakaway faction of Southern Democrats who believed strongly in racial segregation and were opposed to their party's civil rights program. Thurmond joined the Republican Party in the 1960s and ultimately turned away from his segregationist past.

"My father did a lot of things to help other people, even though his public stance appeared opposite," Washington-Williams said. "I was sensitive about his well-being and career and his family here in South Carolina."

Washington-Williams said she went public only at the urging of her children, but rumors had persisted for years.

An attorney for the former senator's family confirmed in 2003 that Thurmond fathered a child with a teenage black housekeeper in 1925. Her mother, Carrie Butler, worked as a maid at the Thurmond family home in Edgefield, South Carolina.

At the time of Washington-Williams' birth, Butler was 16 and Thurmond was 22, unmarried and living in his parents' home.

Butler's sister took the girl to live in Pennsylvania when she was 6 months old. She did not meet Thurmond until 1941, when she was 16.

Her mother, who was ill and died a short time later, had insisted on introducing her to Thurmond, who acknowledged her as his daughter, the Washngton Post reported in 2003.

Throughout the years, the two kept up a relationship despite the divide over race, Washington-Williams said.

"When my father became a United States senator [in 1954], his communication and support continued" she said, and "his financial support was constant during various phases of my life. I knew him beyond his public image."

She said she tried -- to no avail -- to dissuade him of segregationist positions, which produced "mixed emotions" for her.

"I never did like the idea of his being a segregationist, but that was his life, and there wasn't anything I could do about that," she said.