Cruz met his wife, Mildred Ortiz in the town of Río Piedras in Puerto Rico.
He started his career as a professional boxer with a loss, being defeated by decision in eight rounds by Juan José Jiménez, October 23 of 1959 in Santo Domingo.
He lost on points to Graham Dicker in Brisbane, stopped Guizani Rezgui in Sydney and outpointed Gilberto Biondi in Melbourne.
Then he returned to Latin America, his first fight after arriving from Australia being a major step up in quality of opposition for him: In Caracas, he met fellow world champion boxer Carlos Morocho Hernández.
He finished his year by beating Marcos Morales, a boxer of Puerto Rico during this era, at Santo Domingo.
In 1967, he avenged his loss to Narvaez, and went undefeated the rest of the year, securing his position as the world's number one challenger among Lightweights.
He won three more fights to begin 1968, and then, on June 29 in Santo Domingo, he was given his first chance to challenge for a world title.
On February 15, 1970, Cruz was flying back to San Juan alongside his family for a fight against Roger Zami,[1] when their Dominicana de Aviación DC-9 plane crashed into the waters of the Caribbean shortly after take-off, killing Cruz,[2] his wife and two children, along with all other passengers and crew on board, which included the coach and eleven players of the Puerto Rico women's national volleyball team.