Flagg has spoken publicly about being dyslexic.
She has expressed the great challenge of being a writer, saying, "I was, am, severely dyslexic and couldn't spell, still can't spell.
So I was discouraged from writing and embarrassed."
Even though it was clear that she had an affinity for crafting stories, her dyslexia stalled any possible writing career through most of the 1970s.
It was not until a teacher spotted a pattern in Flagg's misspelled written answers on Match Game and sent her a note that she understood she had a learning disability; Flagg later stated she had not heard of the condition prior to this note.
Eventually, Flagg was able to overcome her fear associated with the disorder and has since completed several novels.
In the mid-1970s, Flagg shared a house in Charlottesville, Virginia, with American writer Rita Mae Brown, whom she met at a party in the Hollywood Hills hosted by Marlo Thomas.
According to Brown, Flagg also lived for eight years with former The Bold and the Beautiful actress Susan Flannery.