ORANGE — Without any warning or explanation, Selectboard Chairman Richard Sheridan — who has been at odds with fellow board members over the hiring of a new town administrator — resigned this week.

He announced the news at the beginning of a board meeting Wednesday night, after a lengthy, closed-door meeting with his four colleagues.

In his last act as chairman, Sheridan, 72, asked those in attendance to stand for the Pledge of Allegiance. He then broke the news.

“I have to make an announcement that I really regret having to make, and I don’t want to get into any parameters as to how I came about that,” Sheridan said.

Sheridan, who had another year on his term, turned the meeting over to Vice Chairman Ryan Mailloux, who said he had not expected the resignation.

“It’s been a pleasure doing this job, but I don’t feel I can be effective any longer,” Sheridan said.

The purpose of the closed-door meeting was unclear.

Sheridan has lived in Orange for 47 years, holding several positions in the town government. This was his fourth term as selectman.

In recent weeks, he filed complaints with the state Ethics Commission over arguments with his peers about whether acting town administrator Gabriel Voelker should have been a finalist for the job after she was not recommended by a search committee.

But later, the search committee added Voelker and another person as finalists, and the Selectboard voted last week 4-1 to hire her, with Sheridan against.