[1] His family was a military one; his father eventually reached the rank of major general, and two of his uncles became brigadiers.

[2] Raised as an Army brat, he moved about frequently; but lived most of his early life in Canberra, where he settled.

[3] He completed his doctorate there under the supervision of Peter Dennis,[4] writing his 1985 thesis on "British Commonwealth forces in the Korean War: a study of a military alliance relationship".

[5] Grey joined the Historical Section of the Department of Foreign Affairs, but returned to the University of New South Wales at the new Australian Defence Force Academy (ADFA) campus in 1988, and became a professor there in 2003.

[1][3] The October 2017 edition of The Journal of Military History was dedicated to Grey's memory, and featured several articles by or about him.