The 29-year-old, born without a right leg, trained more than 26 hours a week in the lead-up to the ironman last December, running more than 70 kilometres and cycling 300km.
Mr Garvey said he had never been intimidated or apprehensive about competing in sport.
‘Sport was always my way of being able to prove I could do anything that anyone else could and fitting in,’ Mr Garvey said.
‘As I got older I started wanting to do things that were difficult not only for disabled people but for able-bodied people too.’
The IT specialist and motivational speaker recently won the Yokohama stage of the World Triathlon series after finishing second in Chicago.
Mr Garvey said next year’s World Championships in the US would give him a good idea of where he was at in the rankings, ahead of the 2016 Olympics and Paralympics in Brazil.
After raising more than $20,000 last year, Mr Garvey was able to buy a custom carbon fibre running blade, which he said made an immediate impact on his performance.
‘Running on that, words can’t explain it,’ he said.
‘It doesn’t make it any easier to run, it still hurts as it does for anyone but it feels normal to me, when I land on the blade leg it feels how it should for someone who is running normally.
‘Before I had the running leg the furthest I’d run in my old leg was 12 kilometres and it tore shreds off me.
‘There were blisters and chunks of skin taken off and then my running leg was so well developed and built for me that I managed to finish the 42.2 kilometre marathon without a blister or a scratch.’
Mr Garvey said people needed to be less intimidated by failure.
‘I’m a big fan of failing; I believe you always have to sit on that edge of failure before you can see where you can really push yourself to,’ he said.
Mr Garvey is currently raising funds to develop a specialised leg for cycling to help him in his pursuit of the 2016 Paralympics.