Staff, students and parents were "gobsmacked" when he announced his decision.
Mr Broadhurst said the reaction from students and parents was heart-warming.
"One of the students told me she was leaving the school if I did not stay on. Some of the parents have also urged me to stay on for another three or four years until their children have left the school," he said.
He loved being principal of Omokoroa No 1 School but believed it was time to move on while the school was in a "very healthy" shape.
Joining the teaching profession has been a family affair - his late father taught at Nelson College and his sister was a teacher at an intermediate school in Upper Hutt.
"My wife also teaches at this school. Bridget, who is a bit younger than me, runs the Year 7 and 8 pupils' programme," Mr Broadhurst said.
"But Bridget won't be retiring as we'll probably need the money," he quipped.
"It's been a fantastic journey. There are always be up and downs in any profession, but all the highs have far outweighed any low points.
"It's a very rewarding career but it's also hard work. I don't think lots of people understand that teaching is not a 9-3 job, with 12 weeks holiday every year."
Mr Broadhurst said handing over the reins would free up more time to spend with his five grandchildren and pursue other interests.
"I love teaching particularly maths so I plan to become a maths tutor and I have always wanted to do some voluntary work. Maybe I'll take on some part-time manual work."
Snapshot of Chris Broadhurst's career
1970: Avondale Primary, Christchurch
1971-1973: Tinwald Primary, Ashburton
1974-1986: Ashburton Intermediate School
1986 -1994: Te Miro School, up the back of Cambridge
1994- 1997 Deputy principal at Hamilton West Primary
February 1, 1997: Appointed principal at Omokoroa No 1 School