He was known as a nationalist composer who expressed the Philippines' cultural identity through his compositions.

He was known as a “romantic nationalist.”

He restored the Philippine Constabulary Band in 1945, which was reputedly likened to a symphony orchestra. It was considered as “one of the best military bands in the world.” It would later be renamed the Philippine Army Band.

He was one of the “Triumvirate of Filipino Composers” which includes Antonio Molina and Francisco Santiago.His compositions are Mutya ng Pasig Cavatina for Violoncello, Nasaan ka Irog and Magbalik ka Hirang.

He was one of the New Music Composers, He then embarked on his life’s work, dedicated to the understanding and preservation of Filipino traditional music. For example, Ugma-Ugma.

His major works as composer-conductor were performed at the concert “LAHI”

that featured works by local major composers. e.g. Tubig ng Buhay.

He was awarded the “Philippine Composer of the Century” after receiving the “Composer of the Year Award” in Manila in 1956 and 1957.

His music and compositions are Misa, Four Poems for Soprano and Piano, Te Deum, Kay Ganda ng Ating Musika (1978), as well as the modern zarzuela Alikabok (2003), the opera Spoliarium.

He is listed in “The International Who’s Who in Music.” Cornejo was also known for his extemporaneous thematic improvisations based on the letters of people’s names.