Pierre Arpels (1919–1980) was the youngest son of Julien Arpels and a nephew of Estelle Arpels and Alfred Van Cleef. He became a partner in Van Cleef & Arpels in 1937, at about 18, with his brothers Claude and Jacques and their cousin Renée Puissant, and after the Second World War the three brothers ran the house together.
He is the family member most associated with watches. In 1949 he designed a man's watch for his own use, with a slim round case held by two central attachments; it remains in the collection as the Pierre Arpels watch, which the house presents as its vision of masculine elegance.
With his brother Claude he travelled in India in search of precious stones, journeys which, according to French Wikipedia, inspired the house's Indian-influenced jewels. His New York Times obituary described him as a Paris designer who crafted jewellery for the social set. He also appears in the opening scene of the 1964 film Fantômas, shot in the place Vendôme boutique.
He died in 1980, aged 61.
Sources are thin; Casadi has not read his 1980 New York Times obituary in full, and his exact role in the design of the house's jewellery beyond the 1949 watch is not documented in the sources seen.