His debut came in 1989 against New Zealand, where he impressed his opposite number,
Joe Stanley. In his next Test, he and Little marked the experienced French pair of
Franck Mesnel and
Philippe Sella, and Horan scored his first two Test tries. After winning the
World Cup in 1991, in which he scored four tries and a successful
Bledisloe Cup in 1992, the Wallabies endured a mixed 1993. 1994 saw Horan's career nearly end with a horrific knee injury in the Super 10 final and he would spend over a year in rehabilitation before making the squad to the 1995 World Cup defence in South Africa. In 1996, he captained the national side for the first and only time and he also played at flyhalf. He missed the 61–22 loss to South Africa but returned for a 15-all draw with England, helping Ben Tune and
George Gregan score a try apiece. He peaked again for the
1999 Rugby World Cup against South Africa in the semi-final. He played against South Africa in a 27-21 extra-time win. This was followed by the second Wallaby World Cup win of his career. 2000 was to be his final Test year and was affected by injuries. He signed for English club
Saracens. ==Retirement==