One of his most celebrated roles was that of senior counsel in the Mabo case, which abolished the doctrine of terra nullius and recognized Aboriginal land rights in Australian law for the first time.
Castan spent 10 years preparing and arguing the case on behalf of Eddie Mabo, for which he received widespread acclaim.
[1] In 1985 Castan, along with Uncle Jim Berg, and Ron Merkel, sued the University of Melbourne and the Museum of Victoria for the return of their collections of Indigenous cultural material and through this act created the Koorie Heritage Trust.
[5] Castan was a member of the Smorgon family and a child of Russian Jewish immigrants who migrated to Australia.
[7] After his death, tributes flowed from the legal and political community, and he was described by Senator Aden Ridgeway as "the great white warrior against racism".