Following Cahill's death, the new public high school in Mascot in his former seat of Cook's River also decided to honour his memory, as well as his role in the school's establishment, by naming itself the "J J Cahill Memorial High School", which was officially opened by his widow, Esmey Cahill, on 24 March 1961. On the school's 50th anniversary, the principal Robyn Cowin noted that Cahill "was a man of genuine personal integrity, a family man and a great worker whose deeds spoke for themselves [...] His code of behaviour and indeed the manner of his life embodied the school motto 'Do what is right because it is right'".