Erlanger board member Richard Casavant has resigned after serving about 18 months of a four-year appointment.
Board Chairman Ron Loving announced Casavant's resignation at the monthly board meeting Thursday evening.
Prior to the meeting, Loving said Casavant called him last week to say he planned to resign. Casavant did not give him a reason, Loving said.
"With his experience, it was a great honor for us to have him on the board," Loving said.
Casavant could not be reached for comment Thursday.
A former county commissioner and dean of the College of Business at University of Tennessee at Chattanooga, Casavant was appointed to the position in April 2011 by Hamilton County Mayor Jim Coppinger.
Coppinger said Casavant called him about resigning and also gave him a short letter of resignation.
"He didn't give me any specifics and I didn't ask him for any," Coppinger said. "Richard is a good friend. I have a lot of respect for him."
In 2005, Casavant led a County Commission study of Erlanger after the hospital paid the federal government $40 million to settle an investigation into alleged regulatory violations, according to Chattanooga Times Free Press archives.
More recently, he voted against paying outgoing CEO Jim Brexler a severance package in December after numerous board members voiced disapproval of Brexler's performance.
Erlanger has struggled financially recently, losing $9.5 million in the last fiscal year, but has been in the black this fiscal year.
Coppinger said he plans to appoint someone to fill Casavant's seat. An additional county seat has been vacant since December, but Coppinger said he doesn't plan to fill both positions.
The Erlanger board, which has authority over Chattanooga's public hospital, has had 11 members - four appointed by the county, four by the city, one by the legislative delegation, one by the Chattanooga & Hamilton County Medical Society and one by the Chancery Court.
This year, the legislators passed a law appointing Erlanger's chief of staff as a board member, making it a 12-member board.
Lawmakers have said they may make other changes to the legislation governing the hospital.