In a statement to the Associated Press, Kidder's daughter Maggie McGuane said the family decided to make her mother's suicide public because "it's important to be open and honest about the suicide so there's no cloud of shame".
Her final years were troubled by conflicts with people who were down on their luck that she took into her home.
Kidder's daughter, Maggie McGuane, told the AP that she had known since May that her mother committed suicide.
"It's important to be open and honest so there's not a cloud of shame in dealing with this", she continued.More news: US to impose sanctions on Russia over nerve agent attack
More news: Georgia Hall's dreams come true after famous Women's British Open triumph
More news: Bethesda confirms Fallout 76 won’t be available on Steam
Kidder was found May 13 in her home in the USA state of Montana.
Most recently, Margot appeared in The Neighbourhood, which came out earlier this year.
Canadian-born Kidder had been a mental health advocate during her life with her own struggles well-documented in the media. She returned to the world of Superman in the 2000s with periodic guest appearances on Smallville.
She spoke openly about how she had wandered around Los Angeles for days during that episode, and she said in 2008 that she did not like the words "mental illness". During the interview, she said that she was in bed with the flu, and her voice sounded rough and raspy. Additionally, ambulances were called to Kidder's home five times in seven months, including at the time of her death. Maggie has worked as a photographer, a writer, and occasionally modeled.