Espada began his professional boxing career on March 11, 1967, with a defeat at the hands of future Antonio Cervantes world title challenger Josue Marquez, on a six-round decision, at San Juan.
After one more win, he fought outside Puerto Rico for the first time, losing on points after six rounds to future Roberto Durán world title challenger Jimmy Robertson, on September 27, 1969, at Los Angeles, California.
[3] (In Spanish) He retained the title with a fifteen-round decision over Johnny Gant, and won a non-title fight with an eighth-round knockout over Alfonzo Hayman.
Towards the end of his career, Espada, realizing his best days as a boxer had probably passed him by, announced on the Vea magazine that he was putting together a salsa orchestra.
Espada lost his last important fight, against Thomas Hearns, by a knockout in round four at the Joe Louis Arena, in Detroit, on March 2 of 1980.
Espada wanted to retire as a winner, however, and, after one year of inactivity, he made a one fight comeback, knocking out Julio Alfonso in four rounds, on December 10, 1981, in San Juan.