[1] Hamilton began his Australian Public Service career in 1939 as Army Paymaster for Tasmania.
[1][2] On 1 January 1966, Hamilton was appointed Secretary of the Department of Social Services.
[5] During his time as head of the Social Services department, Hamilton broadened the department's scope by introducing legislation for deserted wives, for home care and for emergency relief.
[1] Hamilton was made an Officer of the Order of the British Empire in 1966 whilst a First Assistant Secretary at the Department of the Treasury.
[6] In June 1972 he was appointed a Commander of the Order of the British Empire during his time as Director-General of the Social Services Department.