He's preparing for his third Paralympics, having won medley swimming gold medals at both Beijing in 2008 and London four years ago.
The versatile Leslie, who is also a Wheel Black rugby player, has a simple motto: "Do it".
It's stood him in good stead as he has persevered without having use of fully formed arms and legs and insists he's never had a 'poor me' attitude.
"If I did my, parents would've shook that out of me and said 'nah mate, not on our watch'."
Instead Leslie, 26, is from the up and at 'em school and is delighted with the fresh perspective given Paralympic sportsmen and women since he first made the New Zealand team in 2006.
"Definitely in my time the way that paralympics sport is viewed has changed significantly.
"Back when I first started, you weren't really compared on a level playing field whereas nowadays my achievements are ranked beside able-bodied counterparts much closer, which shows the credibility paralympic sports are getting.
"We don't do it for a pat on the back. We're not doing it for participation at all. It is about winning."