The elder Gibson was appointed to the chair of philosophy at the University of Melbourne in 1911, and the family moved to Toorak, before relocating to Mont Albert in 1918.
He was an organiser for the British Labour Party at the 1929 general election before returning to Australia in 1931 to work as an extension lecturer for the Workers' Educational Association in 1931.
Gibson became disillusioned with the Scullin government and its failure to deal with unemployment, and joined the Communist Party of Australia in January 1932.
On 16 March 1937, after returning from the World Peace Conference in Brussels, he married Dorothy Alexander in Melbourne.
He was the principal witness before Justice Lowe's royal commission of 1949–50 into communism in Victoria, and was little moved by Khrushchev's revelations about Stalinism in 1956.