He has presented papers on baroque and contemporary music in the United States, Belgium (17th Congress of the International Musicological Society), and Argentina. His music has been performed in concerts and festivals in Argentina, Europe and the US, including Latein Amerika-Ruhrgebiet in Essen, as well as at the World Music Days in Seoul. He was one of five composers commissioned to write a piece premiered in November 2007 in Buenos Aires during the new music series organized by the Complejo Teatral de Buenos Aires. Recent commissions include pieces for Ars Antiquanova Choele Choel and the Bugallo-Williams Piano Duo. 2014 projects include a new work for the Damocles Trio to be premiered at the Look & Listen Festival in May and a monographic concert to be presented at the Centro de Experimentación del Teatro Colón in Buenos Aires in September.
He has been conducting choirs and vocal ensembles for 20 years, and has presented a variety of music from the Renaissance to the twentieth century, specializing in Latin American early music. He is the conductor of the critically acclaimed ensemble Meridionalis, and was the conductor of the Yale International Singers from 1999 to 2005. He also premiered a number of new works for chamber ensembles and orchestra with Yale Philharmonia, New Music New Haven, and NeitherMusic. In addition to performances at venues in the New York area, he has conducted at the Festival de Música Sacra Quito 2013 and the Biblioteca Luis Ángel Arango in Bogota. His teaching experience includes positions as a teaching fellow for music appreciation and American popular music at Yale Department of Music and for hearing and analysis at Yale School of Music. He also taught music history at the Universidad de Buenos Aires and composition at the Universidad Nacional de La Plata, as well as given workshops at Folkwang Universität der Künste, the Chamber Music Center at Wellesley College, and the Clarion Society Collegium.
Sebastián holds a doctorate in composition from Yale University and a licentiate in musicology from the Universidad Católica Argentina in Buenos Aires.