The Oscar-winning actress and partner to Brad Pitt made the announcement in the form of an op-ed she authored for Tuesday's New York Times under the headline, "My Medical Choice." She writes that between early February and late April she completed three months of surgical procedures to remove both breasts.
Jolie, 37, writes that she made the choice with thoughts of her six children after watching her own mother, actress Marcheline Bertrand, die too young from cancer.
"My mother fought cancer for almost a decade and died at 56," Jolie writes. "She held out long enough to meet the first of her grandchildren and to hold them in her arms. But my other children will never have the chance to know her and experience how loving and gracious she was."
She writes that, "They have asked if the same could happen to me."
Jolie said that after genetic testing she learned she carries the "faulty" BRCA1 gene and had an 87 percent chance of getting the disease herself.
She said she has kept the process private so far, but wrote about it with hopes of helping other women.
"I wanted to write this to tell other women that the decision to have a mastectomy was not easy. But it is one I am very happy that I made," Jolie writes. "My chances of developing breast cancer have dropped from 87 percent to under 5 percent. I can tell my children that they don't need to fear they will lose me to breast cancer."
Phone and email messages left by The Associated Press late Monday night seeking comment from Jolie representatives were not immediately returned.
She is anything but private in the details she provides, giving a description of the procedures.
"My own process began on Feb. 2 with a procedure known as a 'nipple delay,'" she writes, "which rules out disease in the breast ducts behind the nipple and draws extra blood flow to the area."
She then describes the major surgery two weeks later where breast tissue was removed, saying it felt "like a scene out of a science-fiction film," then writes that nine weeks later she had a third surgery to reconstruct the breasts and receive implants."
Many women have chosen preventive mastectomy since genetic screening for breast cancer was developed, but the move and public announcement is unprecedented from a star so young and widely known as Jolie.
She briefly addresses the effects of the surgery on the idealized sexuality and iconic womanhood that have fueled her fame.
"I do not feel any less of a woman," Jolie writes. "I feel empowered that I made a strong choice that in no way diminishes my femininity."
She also wrote that Brad Pitt, her partner of eight years, was at the Pink Lotus Breast Center in Southern California for "every minute of the surgeries."
Bertrand, Jolie's mother, died in January 2007. She had small roles in the movies Lookin' to Get Out in 1982 and "The Man Who Loved Women" in 1983. She raised Jolie and her brother after divorcing their father, Oscar-winning actor Jon Voight, when Jolie was a toddler.
Jolie has appeared in dozens of films including 2010's The Tourist and Salt, the Tomb Raider films and 1999's Girl, Interrupted, for which she won an Oscar.
But she has appeared more often in the news in recent years for her relationship with Pitt and her charitable work with refugees as a United Nations ambassador.
Meanwhile, CNN anchor Zoraida Sambolin announced Tuesday that she has breast cancer and is getting a double mastectomy.
Sambolin, who anchors CNN's Early Start morning show, talked about her condition on the show Tuesday while discussing Jolie's decision.