Dominguez was born in Pinilla de Toro, Spain and received his medical degree summa cum laude from the University of Salamanca.
The author of at least 80 books and pamphlets on Catholic topics, Dominguez also had a weekly cable television program, La Biblia Vivida, in Manhattan.
[2] A believer in the alleged apparitions of the Blessed Virgin Mary in Garabandal, Spain, Dominguez worked to promote the prophetic messages given there.
While the 1961–65 apparitions have still not received the approval of Catholic authorities, Dominguez wrote and lectured extensively on these events, and was a close friend of Conchita Martinez, one of the Garabandal visionaries.
He ran for mayor of New York City in 1981 as candidate of the Right to Life Party, earning 30,000 votes but finishing a distant 5th behind winner Ed Koch.