His father was Juan Antonio Ruiz y Lopez de Carvajal, an admiral and a mathematician, and the family tradition was for males to receive naval training.
After starting out on that path, he soon abandoned it in 1904 when he entered a music competition in Cadiz at which one of the judges was Manuel de Falla.
He had earlier had lessons with Salvador Viniegra, a painter, art patron and a cellist of considerable ability, albeit an amateur.
After reaching and surpassing Viniega's standard, he entered the Madrid Royal Conservatory to study under Víctor Mirecki Larramat (who was later to become his father-in-law).
In 1915 he was the soloist in the first performance in Spain of Richard Strauss's Don Quixote, under Fernández Arbós (and in 1925 he played the same work under the composer's baton).
They played complete cycles of Haydn, Mozart and Beethoven string quartets in recitals, in schools and universities, and on international tours.
The composer played the piano, the soprano was Lola Rodríguez Aragón, and the string players were Iniesta, Antón, Meroño and Aroca.
His second wife was Julia Bazo-Vivó, the mother of his only child, Mary Ruiz Casaux (María Pilar Ruiz-Casaux y Bazo; born 1936), a pianist who was the first to perform all of Johannes Brahms' piano works in Spain.