He later became a coach. He coached Miroslav Blažević at NK Rijeka in the Yugoslav First League. and was the assistant manager to Abdulah Gegić at Partizan when they reached the 1966 European Cup Final. He also coached Polish side Legia Warsaw in the season 1964–65. Popescu then managed Swiss team St. Gallen and Wormatia Worms in Germany before moving to Morocco and Algeria to help develop football in those countries, there he coached the Moroccan Olympic side and KAC Kénitra. In the 1972–73 season, he was at the helm of Algerian side JS Kabylie, with whom he won the championship.