Spanish composer, teacher, and musical essayist. He was born on August 5, 1886 in Alicante (Spain). Son of Trino Esplá Visconti and Francisca Triay Quereda. He was the cousin of the politician Carlos Esplá Rizo. He married María Victoria Irizar Góngora on July 18, 1929. He had three children: Amparo, María Luisa, and Gabriel Esplá Irizar.

He started his musical training with Fernando Lloret. He studied piano and harmony with Juan Latorre while he was finishing his high school studies at the Instituto de Alicante. He moved to Barcelona and was admitted into the Escuela de Ingenieros Industriales in 1903. A year later, he stopped these studies and pursued Philosophy and Literature; meanwhile, he took harmony classes with Sánchez Gavagnac. After completing these studies, he graduated as an engineer. He composed "Suite en La bemol" (1910) and won the first prize at the International Competition organized by the National Gesellschaft die Musik of Vienna, with Camille Saint-Saëns and Richard Strauss being part of the jury. He devoted himself entirely to music since 1911. He moved to Vienna and premiered "El sueño de Eros", a symphonic poem inspired by a text by Gabriel Miró; in 1912, it was performed by the Symphonic Orchestra of Madrid under the direction of Enrique Fernández Arbós at the Teatro Real. Influenced by Saint-Saëns, he modified the structure of "Suite en La bemol", and re-premiered it under the title "Poema de niños". He composed "Sonata para violín y piano" in 1915. Serge Diaghilev, director of the Ballets Russes, commissioned him to compose the ballet "Los cíclopes de Ifach" in 1918; Fernández Arbós premiered a concert version of this work years later. He composed "Don Quijote velando las armas" (1924) for the Orquesta Bética de Cámara; and in 1926 he performed the symphonic version. In that decade he also premiered "Nochebuena del diablo" (1924) and rearranged some parts of the "Misteri de Elche". The dancer and choreographer Antonia Mercé La Argentina presented his ballet "El contrabandista" in Paris in 1928. That year he was awarded by New York's Columbia Records for "Suite schubertiana". In this time of great production, he wrote pieces such as "Canciones playeras" (1929); or the piano suites "La Sierra" and "Cantos de antaño" (1930). They were followed by "Sinfonía coral" (1942); "Sonata del Sur" (1943); "Sonata Española" (1949), a work commemorating the First Centenary of Chopin's death, whose Spanish premiere was performed by the pianist Pilar Bayona; "Sinfonía Aitana" (1964); and "Cantata sobre los Derechos Humanos" (1969) based on the text by Gerardo Diego. From his repertoire, it is also necessary to mention other works for the stage such as his operas "La bella durmiente" (1909), "La Balteria" (1935) and "El pirata cautivo" (1974). He published several essays, such as "El arte y la musicalidad" (1912); or "Función musical y música contemporánea" (1955).

He was a professor at the Conservatorio Nacional de Música y Declamación de Madrid from 1930 and was appointed director in 1936; a position he combined with the presidency of the Junta Nacional de Música y Teatros Líricos. Due to his Republican ideology, Oscar Esplá left Spain with his family in the same year and did not return until 1951. His return was facilitated by his friend Germán Bernácer Tormo. In 1955, he became a full academic of the Real Academia de Bellas Artes de San Fernando. He passed away on January 6, 1976, in Madrid (Spain).

Su legado se encuentra depositado en el Centro de Investigación de Legados y Donaciones de Alicante, de la Biblioteca Gabriel Miró (Alicante).