Rugby union Kirwan played for
Marist Brothers Old Boys RFC and
Auckland domestically, winning 142 caps with the latter during an era when the side dominated the
NPC and
Ranfurly Shield. From 1985 to 1989 he also played in Italy, with
Benetton Treviso, where he won the
Italian championship in 1989. Also in the Treviso team was the
All Black Craig Green, Kirwan's teammate in the
1987 World Cup won by New Zealand. After his spell in rugby league, he finished his rugby union playing career with
NEC in Japan from 1997 to 1999.
International Kirwan played 63 test matches for
New Zealand from 1984 until 1994. Kirwan played a major role in the All Blacks' 23-test unbeaten run from 1987 to 1990, including winning the
1987 World Cup. He scored 10 tries in five tests against Wales and Australia during 1988. In all he scored 35 test tries for New Zealand. He also scored 67 tries in all appearances with the All Blacks (including non test matches) which is still the national record. His total of 199 first class tries remains a New Zealand record. Kirwan was selected as one of the "Five players of the year" for the 1985,1986, 1987 and 1988 seasons, in the Rugby Almanack of New Zealand. In 1986 Kirwan and
David Kirk were the only All Blacks not to join the 'rebel'
New Zealand Cavaliers team that travelled to
apartheid-era South Africa after a New Zealand court held that the All Blacks' playing in that country would be inconsistent with their mission of promoting rugby. As a result, he and Kirk were the only ones not barred from playing with the All Blacks after the tour.
Rugby league At age 30 Kirwan signed for the newly formed
rugby league club
Auckland Warriors for the
1995 ARL season, with a mutual option for 1996. Playing on the wing, Kirwan was the Warriors' top try scorer in the
1996 season. He was a staunch opponent of the ARL during the
Super League war. ==Coaching career==