Harold dated Natasha Davies, a fellow Slytherin. He tried to sell a substance that he claimed was powdered dragon claw to students studying for their O.W.L.s. In truth, the substance was dried Doxy droppings, which Hermione Granger confiscated as a school Prefect. Harold later offered to sell Firewhiskey to Dean Thomas and Seamus Finnigan. Later he married Natasha had a daughter named Bridgette, who became a Slytherin like her parents.