O'Reilly completed his law degree at the University of Canterbury and was admitted to the bar in 1963, at the age of 21.[2] In 1967 he became a partner for the Cameron & Co law firm.[2]
O'Reilly played Prop and won senior championships with the University of Canterbury in 1963 and 1965.[2]
Coaching
In 1988, O’Reilly coached the Crusadettes, the University of Canterbury Women's team, and they toured the United States and Europe.[4] A year later he selected the first women's team to represent New Zealand.[3]
O’Reilly had a hand in organising RugbyFest 1990 in Christchurch. It was a two-week women's rugby festival that featured national teams from the Netherlands, the United States and USSR.