He is currently the conductor of Meridionalis, a group dedicated to the performance of early music from Latin America. Watch a performance of José Maurício Nunes Garcia's Judas mercator pessimus
With this group, he has appeared in New York, the Biblioteca Luis Angel Arango in Bogota, and the Festival de Música Antigua Esteban Salas in Havana in 2016. He was the musical director of the Yale International Singers from 1999 to 2005.
He conducted the world and US premieres of Hércules in Mato Grosso, by Esteban Insinger, in Buenos Aires and New York, and Alberto Ginastera's Serenata with ICE in the Naumburg Bandshell in 2016.
Sebastián has been conducting choirs and vocal groups since 1987.

In Buenos Aires, he was the conductor of 14, with which he presented a variety of music, from the Renaissance to the XX century.