Oodgeroo Noonuccal of the Noonuccal tribe of North Stradbroke Island near Brisbane, was a poet and Aboriginal activist. She was born Kathleen Jean Mary Ruska on 3 November 1920 at Bulimba (then in the Shire of Balmoral and from 1925 a suburb of Brisbane). Her parents were Edward (Ted) Ruska, and Lucy, nee McCullough. She was the second youngest of seven children. Her father was a Noonuccal descendant. Ruska's childhood home was One Mile on North Stradbroke Island on the outskirts of Dunwich. She completed her education at Dunwich State school in 1934, at the age of thirteen, and left home to work in Brisbane. In 1941 she enlisted in the Australian Women's Army Service and was discharged in 1944. She married Bruce Walker, a childhood friend, on 8 May 1943. The couple had one son, but later separated. Kath Walker later worked for Raphael and Phyllis Cilento. In 1953, she had a son with the Cilentos' son, Raphael junior.

Kath Walker was involved in numerous organisations. From 1961 to 1970 she was the Queensland State Secretary of the Federal Council for the Advancement of Aboriginals and Torres Strait Islanders as well as an Executive of the Queensland Aboriginal Advancement League and Secretary of the Queensland State Council for the Advancement of Aboriginals and Torres Strait Islanders. She was a member of the Aboriginal Arts Board, the Aboriginal Housing Committee, the Australian-American Bicentennial Committee. She was also the Chairperson of the Cultural Committee of the Queensland Multicultural Task Force in 1978 and later the Managing Director of the Noonuccal-Nughie Education and Cultural Centre.

During her lifetime Kath Walker filled several lecturing and artistic positions. These included Adult Education Lecturer; Delegate to the World Council of Churches Consultation on Racism; Guest Lecturer at the University of South Pacific; Official Australian Envoy on a Diplomatic Passport to International Writers' Conference in Malaysia; Senior Advisor to the Australian Aboriginal Contingent to the First World Black Festival of Arts in Nigeria; Guest of the Government of Papua New Guinea for the PNG Festival of Arts; Delegate to the Second World Black Festival of Arts; Lecturer and assistant to Professor P. Edwards, Camp Jungai pre-tertiary Aboriginal students summer camp; Remedial Tutor at the Dunwich State Primary School. She toured the United States on a Fullbright Scholarship and Myers travel grant lecturing on Australian Indigenous culture.

In 1981 Kath Walker launched her new career as a painter and fabric designer. Her first exhibition was in July 1981. In an article by Bruce Dickson, Kath Walker says that "painting has always been her first love [as] it communicates more effectively than the written word".

In protest at the 1988 Australian Bicentenary celebrations, in 1987 Kath Walker changed her name to Oodgeroo of the Noonuccal tribe. In the same year she returned the MBE (awarded in 1970) to the Governor of Queensland.

She died of cancer on 16 September 1993.