"You compete against the other coaches - it's all about strategy, timing and getting the most out of your team."
He took on a volunteer position at Mokoia Intermediate while on ACC and did a good enough job that ACC sent him on courses. Mackay then got a paid teacher's aide role at Kaitao and, when the job of sports co-ordinator came up, he took that on - on top of his existing workload.
"I had no formal qualifications. I just loved sport and learned on the job by asking heaps of questions."
His passion for sport and for the school's pupils are what gets him to work by 7 o'clock every morning, even though he is often coaching and dropping children home as late as 9.45 the night before.
"It's not about the dollars, it is about the rewards I get when I see kids I have coached five years ago still playing, still enjoying their sport and coming up to say hi."
Mackay said his own physical and learning disabilities provided a great example to pupils.
"I always say to them, if I can do it, you can too and I learn as much from them as they learn from me."
He works in the Wero Matauranga Academy for students who learn through sport, fitness and health.
This year has been the school's most successful in sport, but Mackay focuses on losing as well as winning.
"You play hard and walk off knowing you gave 100 per cent. In life, if you get knocked down and you don't get up again, you won't get anywhere and it's the same in the classroom and in sport."
Principal Rory O'Rourke said he was inundated with responses when he notified staff he was entering Mackay for the award and asked for comments to back up the nomination.
"It is very hard to put into words the support he gives to the students, parents and staff. He is generous with his time, always willing to learn and a man of his word."