It was expected Mr Bolton would apply for the principal's job after it was left vacant by Christina Herrick, who resigned late last year for medical reasons.
Instead, the 46-year-old has decided to return to his family home in Okaihau, in the Bay of Islands, and take over his family's sheep and beef farm.
''My dad passed away when I was 19 and the farm was left to me and my older brother.
''I was too young to take on the farm at the time, and I had other ambitions - I wanted to be a teacher.''
So his brother took over the farm while he carved out a career in education.
Mr Bolton said his brother was now 63 and the physical side of farming was becoming too much, and after 22 years in teaching, he was leaving to follow his call home.
''It will be interesting to learn how to be a farmer again ... Now I'm going to have to work out how to motivate sheep and cattle to do their best.''
Mr Bolton said his departure was ''all about me and my family, not about any reluctance to the job or the school''.
He said it would have been unfair to apply for the principal's job, because he had always intended to take over the farm in the next 10 years.
He and the school would have just settled into his new principalship and he would have had to leave.
''It was circumstances which prompted me to make the move now.''
He would assist the school's new principal in settling into the job, before resigning at the end of this year.
''There's a mix of sadness and excitement.
''I'll miss watching students achieve, and knowing that I played a part in it.''
He said the college was in good heart, and his wife and three children were looking forward to their new life in the far north.
It was unlikely he would return to educating New Zealand's youth, he said.
''Once you make the break, you make the break.''
