He served throughout the First World War with the Aberdeen Line, becoming a second officer, and ultimately receiving his master mariner's certificate in 1921.

He was promoted to lieutenant commander on 30 June 1936, and called up to active duty on 4 September 1939, the day after Australia declared war on Germany.

He was initially posted to HMAS Penguin, the shore base in Newcastle, New South Wales, where he served with the Examination and Naval Control services.

On 16 December 1944, he embarked on a six-month trip to Ceylon, Egypt, England and the United States to consult the records there before returning to Australia.

[1][6] After the war Gill became editor of the journal Navy, and, commencing in the early 1950s, the South Melbourne Record, an independent weekly suburban newspaper.