Her death was announced on the website of the Norman Mailer Society, which said she passed away "after a long and valiant struggle with cancer."
As Norris Mailer wrote in her 2010 memoir, "A Ticket to the Circus," she was a single mother in her mid-20s when she met the then-52-year-old Norman Mailer at a 1975 party in Russellville, Ark. Their attraction was immediate, even if he was breaking up with his fourth wife and seeing the woman who would become his fifth. Norris Church became No. 6 in 1980. A son, John Buffalo, had been born two years earlier.
"I don't know … I was stupid, naive or brave," she told The Times in April. "I just knew that New York was where I wanted to be. I thought, 'If this doesn't work out, I'm a strong, smart girl. I'll figure something else out.' In your 20s, everything seems possible. Something was calling me here, to New York."
Through her husband, she met Jacqueline Kennedy, Imelda Marcos, Woody Allen and Fidel Castro. Norman Mailer could talk about anything; she likened their banter to the rapport between Spencer Tracy and Katharine Hepburn.
But he also discouraged his wife's work, avoided her when he learned she had cancer and had affairs with several women.
"Norman was competitive with everyone," she told The Times in April. "He had to be the best writer in the world. I didn't see it as a contest."
The tension became public by the early 1990s through gossip columns and in an ABC television interview, in which she told Sam Donaldson that "one day Norman is a lion, the next day he's a monkey. Occasionally he's a lamb, and a large part of the time he's a jackass."
They drifted, but eventually she stayed.
"I knew I was going to be with him for the rest of my life, and I think he felt the same way," she wrote. When he died in 2007, she was at his side.
Norris Church Mailer was born Barbara Jean Davis on Jan. 31, 1949. By age 3 she had won a contest as Miss Little Rock. She attended Arkansas Polytechnic College and dated a childhood acquaintance, Larry Norris.
They married in 1969 and had a son, Matthew, two years later. They divorced in 1974.
As she began a modeling career, she changed her name to Norris Church, the last name suggested by Mailer because she attended church often as a child.
The newly single Church enjoyed "a string of boyfriends," including Bill Clinton, then a candidate for Congress.
In addition to "A Ticket to the Circus," she wrote the novels "Windchill Summer" in 2000 and "Cheap Diamonds" in 2007.
Her paintings were featured in several one-woman shows. She was a member of the Actors Studio, appeared in the television adaptation of Mailer's classic "The Executioner's Song" and had a brief part, with her husband, in the film version of "Ragtime." She worked as a model for the Wilhelmina agency.
A complete list of survivors was not available, but she told The Times in April that in addition to her two sons she had two stepsons, five stepdaughters, two grandchildren and "either 10 or 11" step-grandchildren.