He joined the Hiroshima Toyo Carp in 1996 as a second-round draft pick. During his early career, he was overshadowed by the 1996 first-round draft pick, Toshikazu Sawazaki, who was the same age as Kuroda and won the Japanese Rookie of the Year award in 1997. However, Kuroda gradually built up his status to become a consistent part of the starting rotation while Sawazaki began to fade away. In 1999 he pitched in the International Cup held in Sydney, and marked a win against Korea and a complete-game shutout against Taiwan.