Marion Miller Knowles was the daughter of James Miller, gold buyer and general merchant. The biographical roll in 'Twixt Heather and Wattle: The First Minute Book of the Australian Literature Society, 1899-1903 describes her as a poet, novelist and short story writer. Her name first appeared in the ALS minutes on 4 October 1899. Between 1899 and 1927, as 'Aunt Patsy', she compiled the children's page and a women's column for the Melbourne Advocate. She was also a school teacher and devoted time to the Roman Catholic Church in the area of social welfare.
J. Roy Stevens has discussed Knowles's life and work in Adam Lindsay Gordon and Other Australian Writers (1937, pp. 44-50). In recognition of her services to literature Knowles was awarded an OBE in 1938.