Trenholm is an attorney who handles primarily trial and appellate litigation with the firm of Pratt-Thomas Walker, P.A. in Charleston. His practice includes land use and environmental matters as well as conservation easements. He has served on the board of local conservation and preservation organizations and currently sits as a trustee of the Lowcountry Open Land Trust. He and his wife Susan, live in downtown Charleston, escaping when they can to their retreat on close-by Wadmalaw Island.