 After winning five national amateur championships in Puerto Rico, Trinidad debuted as a professional when he was seventeen, and won his first world championship by defeating Maurice Blocker to win the IBF welterweight title in 1993.He held the title for 6 years, 8 months and 14 days.As his career continued, he defeated Oscar De La Hoya to win the WBC and lineal welterweight titles in 1999; Fernando Vargas to win the unified WBA and IBF light middleweight titles in 2000; and William Joppy to win the WBA middleweight title in 2001.