Sir William Adair was born in 1850. Educated in England he joined the Royal Marine Light Infantry in 1867 and served in South Africa during the Boer War. He later became a General.
The Adairs were a prominent landowning family. Sir William was an important figure in Antrim holding the position of High Sheriff at one time. He was involved in the Ulster Unionist Party and was Commander of the Antrim Ulster Volunteer Force. His military background was invaluable in this role. He took charge in the successful Larne gun running operation.