 As a young man, Alexander graduated from Harvard College in 1769, and then moved to Plymouth County, MA where he taught school in the towns of Kingston and Plymouth and became a member of the Old Colony Club celebrating the Plymouth landing.In 1772 he moved to Portsmouth, NH where he worked surveying and exploring the lands of the Royal Navy Timber.When not surveying, he kept a school at Berwick, was one of the proprietors of the town of Shapleigh, ME.