In 1985, Giordano was sold to Napoli for 5 billion lire. In Naples, along with Diego Maradona and later Careca, he formed the famed "Ma-Gi-Ca" front line. Giordano was instrumental in Napoli's first historical "scudetto" win of 1987; he also helped the team to win a rare domestic double that season by capturing the 1987 Coppa Italia that year, finishing as the top scorer of the competition with 10 goals. He later played for Bologna and Ascoli, before turning to a coaching career.