Amy Witting was born in the Sydney suburb of Annandale, and was brought up as a Catholic. She has "melancholy memories of a repressive family life" and remembered the nuns at her school, St Brendan's College, as being "obsessed with the torments of hell". She suffered from tuberculosis as a child.
She went to Fort Street Girls' High School. She studied languages at the University of Sydney where she met, among others, James McAuley, Harold Stewart and Dorothy Auchterlonie. Subsequently she gained a Diploma of Education at Teachers College and became a school teacher. Her tuberculosis recurred in her early adulthood, resulting in her spending time in a sanitorium which "gave her, for a time, the peace and solitude she always craved".
On 28 July 1934, when Witting was 16, one of her poems, written under the pseudonym De Guesclin, was published in the Sydney Morning Herald. Witting always wrote under a pseudonym. Her name, Amy Witting, is from a promise she made to herself to "never give up on consciousness', not be unwitting, but to always remain 'witting'".
Witting married Les Levick, a fellow high school teacher, in 1948, and they had one son. Greg. She continued to write until her death, dying of cancer a few weeks after the publication of After Cynthia, her last novel, in 2001.