In the 1994 South African tour of New Zealand, Otago beat South Africa for the first time to secure the Springbok head. John Leslie running on an angle scored Otago's only try under the posts in very wet conditions in the 19–12 victory.[2]
Leslie qualified for Scotland through a paternal grandfather and initially joined Glasgow Caledonians, making his international debut along with his brother against South Africa in November 1998. Shortly after his debut, he joined the Fukuoka Sanix Bombs club in Japan.
In the 1999 Five Nations championship, Leslie scored the fastest ever try against Wales, touching down after ten seconds after the kick-off. He was voted Man of the Tournament.
Since 2006 to present Leslie now runs the LeslieRugby Business. A rugby product business based in Dunedin, New Zealand.
Leslie also runs one-day training programmes of rugby skill coaching and drill training for children and coaches across New Zealand.
For the 2022 club rugby season, Leslie is returning to coaching, this time with Southern Rugby Football Club, with former All Blacks Kees Meeuws and Jamie Joseph.