Plácido Domingo's parents were both singers of zarzuela, Spain's distinctive national form of musical theater. They founded their own zarzuela troupe in Mexico, where Plácido appeared with them in child roles. He studied voice with Carlo Morelli at Mexico's National Conservatory (1955-1957), and took the small role of Borsa in Verdi's Rigoletto with the National Opera in Mexico City in 1959. His first appearance in a leading tenor role was as Alfredo in Verdi's La Traviata in Monterrey, Mexico, in 1961, and he made his U.S. debut the same year as Arturo in Lucia di Lammermoor with the Dallas Civic Opera.
Domingo's New York debut was as Pinkerton in Puccini's Madama Butterfly at the New York City Opera, October 17, 1965. After a 1966 stadium performance, his debut on the Metropolitan Opera stage occurred on September 28, 1968, as Maurice de Saxe in Adriana Lecouvreur. His first appearances at major houses such as Milan's La Scala (1968), the Vienna State Opera (1967), and London's Covent Garden (1971) established him as one of the greatest lyric tenors of his time, and, remarkably, as a formidable dramatic tenor besides. He has a bright, forceful voice, excellent stage presence, and superb musicianship, studying his parts from full orchestral score when possible. Commanding one of the largest active repertories among his contemporaries, he is often called upon as an emergency substitute. In one memorable case he flew from Europe to San Francisco, studying his part while in the air. He was met by a limousine and changed into his costume while traveling to the opera house by police escort.
Domingo is noted for his musical interests beyond singing. He began conducting, making his debut with La Traviata at the New York City Opera in 1973. He conducted La Bohème at the Met, and commissioned the opera Goya, on the life of the great Spanish painter, from Gian-Carlo Menotti, appearing as the painter in the work's premiere in Washington, D.C. If he had taken up conducting as a hedge against vocal decline, the measure proved unnecessary. Little diminishment is evident in his singing; he has used the darkening of his voice to his advantage, moving further into the dramatic tenor repertoire and even taking on Wagnerian roles such as Lohengrin, Parsifal, and Tristan. He has been especially identified with Verdi's Otello, and appeared in the work's official 100th anniversary performance at La Scala in 1987.
For much of his career he was put forward as a rival with his near-contemporaries, the Italian tenor Luciano Pavarotti and fellow Spaniard José Carreras. When Carreras was hospitalized for leukemia in the 1980s, Pavarotti and Domingo both visited him, and the three brought to an end whatever rivalry might actually have existed. After Carreras' recovery, the three operatic stars formed an unprecedented partnership founded on their common love of soccer. They united every four years at the World Cup tournament for a monster gala concert called "The Three Tenors." The compact discs and video releases of these events then went on to become immense best sellers.
In later years Domingo appeared in concerts for Mexican earthquake relief and AIDS benefits, and has sung and conducted increasingly in zarzuela presentations, on stage and in recordings. In 1993, he founded the "Operalia" competition for young singers. He also turned to administration, becoming artistic director for the Washington Opera (1996) and the Los Angeles Opera (2000).