He said the academy had become a spur for him to attend classes on time and "just show up for school even".
"It showed me there was a different path from my old habits of showing up late to class or not coming to school. It's made a difference at home too, more self-discipline and helping out at home you know, like doing dishes."
At least four of the 14 students from the academy, which includes four female pupils, were seriously considering a military career and another is keen to join the police force.
Seventeen-year-old Bailey Peterson said the course had helped each student focus on the military as a potential career regardless of their eventual choices.
"It made everybody at least think about the military. When I joined I thought I knew what I wanted but then I was shown there was more out there than I knew."
Mr Matiaha said the academy, which is run through the Ministry of Social Development for students considering military careers, focused on leadership, self-discipline, fitness, motivation and teamwork.
Very high standards of behaviour, punctuality and attendance were required of students, and elements within the academy curriculum included English, mathematics, health and fitness, service knowledge, physical training, bushcraft navigation, camouflage and survival, vehicle maintenance and career-focused learning.
Mr Matiaha said that in 1980 he had joined the NZ Army as an infantryman straight out of the then Makora College.
He had been two decades with the army and had served in East Timor and twice completed "stints" in Singapore.
After his discharge he had gone on to work for about a decade with at-risk youth in Pukekohe.
He said the academy was for him "an ideal opportunity to give back to the college and the community that had given me so much before I left 32 years ago".
A graduation parade for academy students featuring certificates and trophies - similar to those presented at actual military parades - will be held at the school on November 16.
Carterton Mayor and former career soldier Ron Mark will be Reviewing Officer, Stuart Wilton will be the Parade Commander and Ms Peterson will be Drill Sergeant.