John Colin Slater was born on 13 January 1913 at Bathurst, New South Wales, to William Edward Slater and Mabel Theresa Dennet. Slater apprenticed as a fitter with the New South Wales Government Railway for five years before working as a fitter and turner.

He joined the militia on 4 May 1931 at Paddington, New South Wales and served with the 2nd Division Signals as a signalman. Slater was discharged from the militia on 12 December 1933 and enlisted in the Royal Australia Air Force on 17 August 1936 with the rank aircraftman class 1. In order to support his family he asked to be discharged, which was approved on 16 March 1937. Slater married Alice Anne Lidgerwood at Woollahra, New South Wales in 1940.

John Slater travelled to Malaya where he joined the Federated Malay State Volunteer Force. He was captured on 15 February 1942 while at Alexandra Road Military Hospital with shrapnel wounds in his legs. Slater was initially taken to Changi and later worked on the Burma-Thailand Railway. He was awarded the Military Medal (gazetted 5 March 1942).

After the war, Slater returned to Australia and worked as an engineer. From 1949 to 1980, he and Alice split their time primarily between Richmond, New South Wales and McPherson, Queensland. At this time John Colin Slater’s date of death is not known.