In 1971, he went to study composition and conducting at the Mannes College of Music in New York City and three years later made his debut performance at Carnegie Recital Hall.
[1][2] Since 1984, Dadap has been the artistic and musical director and principal conductor of the Children's Orchestra Society (COS) in New York City.
Dadap had also been given the Asian-American Alliance for the Arts Award for composing the Handurawan Dance Suite, a work that was premiered by the Brooklyn Philharmonic's Chamber Orchestra in 1988.
On December 7, 2007, Philippine President, Gloria Macapagal Arroyo, presented Dadap the Pamana ng Lahi Award at the Malacañan Palace.
[1] As a conductor, Dadap has worked with violinists Cho-Liang Lin, Soovin Kim and Sarah Chang, pianists Cecile Licad and Emanuel Ax, cellist (and brother-in-law) Yo-Yo Ma, flutist Paula Robison, and most recently Jaime Laredo and Sharon Robinson.