Born in Tokoroa, Mr Crawford was just 18 months old when his family moved to Okaihau before moving to One Tree Point when he was 6.
Having lived close to the water's edge, joining the navy always appealed to the former Bream Bay College student who also completed a degree in science and mathematics at the University of Auckland while working for the navy.
His degree will help him in navigation and navy operations.
Mr Crawford said people he knew encouraged him to take part in the Invictus Games for which he was training hard.
"I am focusing more on athletics and rowing. Swimming is part of my rehab anyway. I'd like medals in a couple of events but at the end of the day, I want to enjoy the environment."
He will competed in the 400m and 1500m track events.
Mr Crawford hoped he had no relapses of the multiple sclerosis while in Canada.
"This is an opportunity to prove those who would doubt or discriminate based on a diagnosis that I am the same person I was when I joined the navy."
He said it was humbling to train and compete alongside people who had worked through and overcome adversity in their lives.
"I see competing at the Invictus Games as a way of proving that no one should be defined or constrained by their injury or in my case their diagnosis.
"They are a means of supporting the rehabilitation of those who are used to a performing at a high level but for injury or illness have not been able to maintain this."