While still a baby, Ruth's family moved to the Cherbourg Settlement. At the age of four, Ruth, along with her sister, was separated from the rest of the family and confined to dormitory accommodation until she was fourteen. After working for many years in domestic service, Hegarty married Joe Hegarty and raised a family of eight children.
Ruth Hegarty was a founding member of Koobara Aboriginal and Torres Strait Islander Family Resource Centre, president of the Brisbane respite centre Nalingu and has for many years been involved on a volunteer basis with projects for the young and the elderly. In 1998, she was awarded the Premier's Award for Queensland Seniors Year, for services to the community. In 1999, she served as the Queensland representative on the National Committee for the International year of Older Persons. In 2007, she was a member of the Queensland Stolen Wages Working Group for the Senate enquiry into stolen wages of Aboriginal workers.
Hegarty's story was recorded by the National Library of Australia for the Bringing Them Home oral history project and appeared in the associated publication Many Voices: Reflections on Experiences of Indigenous Child Separation edited by Doreen Mellor and Anna Haebich (2002).
Her two autobiographies appeared in 1999 and 2003. After a hiatus, she returned to publishing in 2015 with a series of children's books published by Scholastic Australia.