[2] There he was treated with kindness, sent to the local school, and met other future Aboriginal leaders and activists, including Gordon Briscoe, John Kundereri Moriarty, Richie Bray, Vince Copley, Charles Perkins, and others.
[3][4] Cooper was noticed as an up-and-coming player in the junior ranks, winning the "most improved" award for Port Adelaide Colts in 1953.
[9] Cooper met and lobbied Prime Minister Sir Robert Menzies in 1963 in Canberra as part of a delegation to promote justice for Aboriginal people,[8] and in 1964 founded the Aborigines' Progress Association in Adelaide, becoming its first president.
[10] The association was formed in response to perceptions that the South Australian Aborigines' Advancement League of South Australia was dominated by non-Aboriginal members, lessening the voice of Indigenous Australians politically.
[11] Cooper died prematurely of a brain haemorrhage in his twenties or thirties after being flown up to Darwin from Tennant Creek.