[1] Trinidad Sr. began his professional boxer career by taking on 9-1 Nick Ortiz on March 31, 1975, in San Juan, losing by sixth-round knockout.
Trinidad Sr. lost two of his next three bouts and took time off boxing from 1976 to 1978, when he returned on January 14 with a victory over 1-2 Fernando Rivera by six rounds decision at Carolina, Puerto Rico.
Next, Trinidad Sr. had his first fight abroad, against up-and-comer, future WBC world Featherweight champion and International Boxing Hall of Fame member, 31-1-1 Salvador Sanchez.
This bout took place on August 7, 1979, at The Summit in Houston, Texas, United States, and Trinidad Sr. lasted until the fifth round, when he was stopped by the young Mexican.
[4] During 2012, Trinidad, Sr. along with his son and others like former baseball player Juan González and sportscaster Rafael Bracero, was inducted into the Puerto Rico Sports Hall of Fame.
[8] On February 13, 2023, the Trinidad's reached a confidential agreement to solve their problems with their debtors, including Banco Popular de Puerto Rico, without going to court.