"Our goal was to [find] a headmaster who understands and respects Hereworth's fine traditions and philosophy, and who will continue to build on them to further strengthen our school's reputation for developing well-educated and well-rounded boys," Mr Todd said.
"We were impressed with [Stephen's] teaching credentials, his team-building and leadership skills, and his views on and insights into boys' education."
Mr Fiet will start Monday, July 20.
One of his strengths is an understanding of the way in which students adapt to technology, and its use within a classroom environment.
"It can be a tool rather than a substitute for learning that's a good quality he can bring, he's the whole package - he's a family man as well."
Mr Fiet began his career in Scotland in 1994 before moving to New Zealand in 2003. Since then he has taught at various schools in the Auckland area.
With three children and a wife from Southland, the provincial lifestyle was a drawcard, while stepping into a top role was the next step professionally.
Mr Fiet replaces Ross Scrymgeour, who resigned earlier this year after 13 years in the role of Headmaster.