[2][3] He attended Narrabeen Boys' High School, where he began playing water polo, and graduated from the Sydney Law School with a Bachelor of Laws in 1972; he has been a solicitor at the Supreme Court of New South Wales since then.
[3][4] He competed in the Australian water polo team at the 1972 Munich, 1976 Montreal, 1980 Moscow, and 1984 Los Angeles Summer Olympics (the last of which he captained).
[6] He has been Vice President of the Australian Olympic Committee since 2001, was a member of the International Olympic Committee Athletes' Commission from 1988 to 1999, and has served as Treasurer, Vice President and Patron of Australian Water Polo since its founding in 1982.
[3][5][6][7] Montgomery was the inaugural President of the World Olympians Association, a position he held between 1995 and 1999.
[6] Montgomery received a Medal of the Order of Australia in 1986 and was promoted to membership status in 2006.