From 2004 to 2017, he was the Artistic Director of The American Boychoir, leading the ensemble in over 150 performances and up to five national and international tours annually. He has prepared choirs for appearances with the Los Angeles Philharmonic, LA Opera, San Francisco Symphony, New York Philharmonic, Philadelphia Orchestra, Chicago Symphony Orchestra, Berlin Philharmonic, and London Symphony Orchestra.

He has worked with such conductors as Gustavo Dudamel, Marin Alsop, Pierre Boulez, Yannik Nézet-Seguin, Michael Tilson Thomas, and Valery Gergiev, as well as artists ranging from cellist Yo‐Yo Ma, trumpeter Wynton Marsalis, pop legends Billie Eilish, Beyoncé Knowles, Sir Paul McCartney, Josh Groban, and opera singers Kathleen Battle and Jessye Norman. He conducted The American Boychoir on six recordings and led its performances on the Academy Awards and a 9/11 Memorial Service broadcast globally on CNN.Malvar-Ruiz was the music director for the film Hear My Song (Boychoir), starring Dustin Hoffman, Kathy Bates, Debra Winger, and Josh Lucas.

Malvar‐Ruiz previously served as The American Boychoir’s Associate Music Director from 2000‐2004 under James Litton. An expert in the adolescent voice, he has guest conducted children’s and youth choirs around the globe. He earned a Master’s degree in choral conducting from Ohio State University and completed coursework toward a Doctoral degree in choral music from the University of Illinois.