He served as the Prelate of Coronel Oviedo in Paraguay from 1961 to 1976, and auxiliary bishop of the Archdiocese of Newark from 1976 to 1991.
Born in Brooklyn, New York, Pechillo was ordained a priest for the Third Order Regular of St. Francis of Penance on June 10, 1941.
While remaining prelate of Coronel Oviedo, Pope Paul VI appointed him as the Titular Bishop of Nova Sparsa on October 20, 1965.
Pope Paul named him the Auxiliary Bishop of Newark, in the U.S., on March 6, 1976.
Pechillo continued to serve as an auxiliary bishop until his death at the age of 71 on January 1, 1991.