He attended Trinity College at the University of Dublin and graduated in 1882 with an MA. A degree in civil engineering followed in 1885, at which time he was apprenticed to Bindon Blood Stoney, who was engaged in a project to widen and dredge the entrance to the Port of Dublin. After he finished his training, Westropp became the assistant surveyor for County Meath, but soon abandoned his professional work to pursue his archaeological interests. He spent the remainder of his life researching antiquities along the western seaboard.