[1] In 1920 Foster was appointed as union advocate to the royal commission on the basic wage and successfully argued for an increase, although the recommendation was not implemented.
In 1924 he was counsel assisting the royal commission on the 1923 Melbourne police strike, and in 1926 represented the New South Wales and Queensland Labor governments in the Commonwealth Court of Conciliation and Arbitration case regarding standard working hours.
In 1927 he resigned all political positions to become a judge in the County Court of Victoria; while he enforced the written laws he continued to advocate reform.
Despite being considered early in his term as a champion for the unions, he decided against eight officials who defied the Chifley government's emergency laws against assisting strikers in 1949.
In 1952 he was assigned to the maritime industry and encouraged the replacement of outdated vessels, created a new seamen's award in 1955 and adjusted it to placate shipowners in 1960.