Harper, a native of Suffern, N.Y., began her career as a dancer at Radio City Music Hall, then transitioned into theater and improv comedy before ultimately rising to stardom as Rhoda Morgenstern on "The Mary Tyler Moore Show," earning her a Golden Globe and four Emmys.
She got her own spinoff, titled "Rhoda," from 1974 to 1978, then starred in her own sitcom, "Valerie," from 1986 to 1987. She appeared regularly on television for more than 30 years, as well as in a dozen films.
Harper, who beat lung cancer in 2009, was diagnosed with a form of brain cancer called leptomeningeal carcinomatosis in 2013. The disease is incurable, and Harper was reportedly told at the time she would only have months to live. However, she survived for six years thanks to her medical care.
In July, Harper's husband, Tony Cacciotti, whom she married in 1987, revealed her doctors recommended she go into hospice care, but at the time he refused to allow it.
"I have been told by doctors to put Val in Hospice care and I can’t [because of our 40 years of shared commitment to each other] and I won’t because of the amazing good deeds she has graced us with while she’s been here on earth, he wrote on Facebook.
"We will continue going forward as long as the powers above allow us, I will do my very best in making Val as comfortable as possible," he added. "There are two special ANGELS on this planet masquerading as humans who live and work together, that have made it possible to have all of Val’s needs taken care of."
Cacciott went on to say: "For those of you who have been in this position, you will totally understand that 'it’s hard letting go.' So as long as I’m able and capable, I’ll be where I belong right beside her."
Harper's medical expenses proved nearly unbearable, leading her family to resort to crowdfunding to pay for her cancer treatments and care.
Harper herself told Fox News in 2017 that she was used to beating the odds.
“People are saying, ‘She’s on her way to death and quickly,’” she said. “Now it’s five years instead of three months… And the thing is, everyone is going to die in one way or another. So why don’t you fight it? I’m going to fight this. I’m going to see a way.”
Harper was happy with how her life turned out, gushing over Cacciotti's gifts as a caregiver and relishing her illustrious and lengthy career.
“I’ve had a wonderful career. “I got to be an actress. I was a dancer. And then I grew into this area of acting and that was just so wonderful,” she said.
Harper is survived by her husband, Cacciotti, whom she married in 1987, and their daughter, Cristina.
Fox News' Tyler McCarthy, Mariah Haas, Julius Young and Stephanie Nolasco contributed to this report.