John Barter, a retired business executive, resigned his seat on the Charleston County School Board on Sunday afternoon.

Barter explained in a letter to board Chairwoman Cindy Bohn Coats that he had accepted an offer from Spring Hill College in Mobile, Ala., to serve pro bono as its chief operating officer for one to two years. He plans to stay in Charleston and commute weekly to Mobile.

“In the two weeks since this has been announced, I have had time to consider the changes I must make in my life to devote the needed time to Spring Hill,” Barter wrote. “It has become clear to me that I cannot possibly continue to manage the substantial time commitment required to serve on the Charleston County School Board.”

Barter is a graduate of Spring Hill College and previously had served on its Board of Trustees for 15 years, four of which he was chairman.

Barter made his resignation from the nine-member Charleston County School Board effective immediately. His professional career included serving as chief financial officer for AlliedSignal, now known as Honeywell Inc., and president of AlliedSignal Automotive Inc.

He was elected in November 2012 to a four-year term to one of the West Ashley seats on the board. State law calls for the county Legislative Delegation to appoint someone to the vacant post until an election can be held next fall. The delegation’s recommendation would go to Gov. Nikki Haley for approval.

Reach Diette Courrégé Casey at @Diette on Twitter or 843-937-5546.