Born in Boutoupa, Lopy is a product of Diambars. He signed a trainee contract with Sochaux, and signed a professional contract with the Ligue 1 club in 2012.[1] After five years with the Montbéliard side, his contract was not extended, and he signed with Boulogne of the Championnat National.[2]
On 25 January 2023, Lopy joined Nîmes in Ligue 2 for a season.[3][4] At the end of the season with Nîmes, Joseph Lopy remains in Ligue 2. He joined Angers SCO in July 2023 by signing a contract which covers two seasons.[5]