Miranda Marín held top positions at Empresas Díaz and the San Juan Cement Co. from 1979 to 1990, among them treasurer, executive vice-president, and co-chairman of the board.

[1] His candidacy had been considered by the Popular Democratic Party (PPD by its acronym in Spanish) to be a viable contender for the Governorship of Puerto Rico.

William Miranda Marín served for 36 years in the Puerto Rico National Guard starting as Private E-1 enlisted citizen-soldier in 1959.

[2] On June 4, 2010, at 7:45 in the morning, Miranda Marín died in the Auxilio Mutuo Hospital in Hato Rey, Puerto Rico, after battling his illness.

The building of the institutional trust of the National Guard of Puerto Rico on State Road #1 from Caguas to Río Piedras at the former facilities of Euro Bank, was posthumously named General William Miranda Marín.