YARMOUTH, Maine — North Yarmouth Academy’s top administrator, Brad Choyt, will resign at the end of the school year.

Choyt, who has served as NYA head of school since 2011, will step down June 30. In an interview Tuesday he would not disclose the reason for his resignation.

The NYA Board of Trustees has launched a search for Choyt’s replacement, a process that may take as long as a year, Director of Marketing and Communications Kristi Belesca said.

The board has appointed John Drisko, the current assistant head of school, to serve in the interim as acting head. Drisko also directs NYA’s upper school, comprising grades nine to 12, but will temporarily turn over that duty to math department Chairman Eric Austin.

NYA, with a campus at 148 Main St., is a private, coeducational school with 260 students.

In a news release, board President Steve Bachelder called Choyt “a catalyst for innovation and an inspired voice to the community.” Under his leadership, NYA expanded its curriculum and added a Montessori-style program that serves toddlers to fourth-graders.

Before joining NYA, Choyt was head of school at The Blue School in New York City. His prior experience includes serving as an arts and humanities teacher and associate chaplain at St. Paul’s School in Concord, N.H.

A Yarmouth resident who is married and has three children, Choyt would not say exactly what his professional plans are. But he added that he is “looking at opportunities to do meaningful education work in the future.”

“I am grateful for my three years at our school, ones that have been enriching both professionally and personally, and I am incredibly proud of all that we have accomplished as a school during my tenure,” he said.