When Cayabyab was six years old, his mother died due to cancer and shortly prior to her death at age 43 requested that the none of her children take up a career in music.

By age 14, he was able to perform Johann Sebastian Bach's preludes and a solo piano reduction of George Gershwin's Rhapsody in Blue.

[8] Cayabyab initially took up a bachelor's degree in business administration major in accounting at the University of the Philippines, Diliman,[6] as a way to honor his mother's request.

[8] In 1972, Cayabyab became involved with the Philippine Madrigal Singers and became acquainted with Victor Laurel who is a reputed film and theater actor at the time, who often worked with actress-singer Nora Aunor.

[10] As music director, conductor and accompanist, Cayabyab has performed in the United States with leading Philippine music figures, at venues including Avery Fisher Hall in the Lincoln Center in New York City; Carnegie Hall (both the Main and Recital halls) in New York; the Kennedy Center and the Washington Convention Center in Washington, D.C.; the Shrine in Los Angeles; the Orpheum in Vancouver; and Circus Maximus of Caesars Palace on the Las Vegas Strip.

He has worked in the same shows with Sammy Davis Jr. and Frank Sinatra, as well as conducted the Philippine Philharmonic Orchestra for special performances of American jazz singer Diane Schuur and pianist Jim Chappel.

He has produced albums of the popular Filipino teen group Smokey Mountain, Broadway and West End's diva, Lea Salonga, and Spain's internationally acclaimed singer Julio Iglesias.

In 1987 he rearranged the classical tinged version of ABS-CBN jingle (composed by Dominic Salustiano), which was used in the network's Station ID from 1987-1995.

Among his many works, his theater musicals El filibusterismo (1993) and Noli Me Tángere (1995) have won acclaim and have been performed extensively in the cities of Japan in 1994 and 1996.

In 2011, he lent his genius once more by composing music for the concert Ageless Passion (libretto by Kristian Jeff Agustin), which was commissioned by the family of retired Chief Justice Artemio V. Panganiban, and staged at the Meralco theater.

In 2006, Cayabyab signed on as a resident judge for the first season of Philippine Idol, offering critiques for the contestants on the reality-talent show.

He was chosen by the top guns of Philippine Idol, while the other two judges, Pilita Corrales and the late Francis Magalona, had to undergo auditions.

In 2019, Cayabyab composed the theme song for the 30th edition of the Southeast Asian Games, "We Win as One"; with lyrics by playwright Floy Quintos, and sung by Lea Salonga.

He became the first recipient of the Antonio C. Barreiro Achievement Award on May 4, 1996, for significant and lasting contributions to the growth and development of Filipino music.

But in a swift and silent move, the big cheeses at San Miguel Corporation (SMC) have already disbanded the SMMC and the SMPO.

[4] In September 2019, the Ramon Magsaysay Award was presented to Cayabyab – the only Filipino among the honorees in 2019 – recognizing him for "showing us all that music can indeed instill pride and joy, and unify people across the many barriers that divide them."

[20] Cayabyab is a devout Roman Catholic, having written various masses and other religious compositions throughout his career, including the song "Say Yes to Life" which he wrote with Steve Latorre and Louie C. Reyes for the Pro-Life Philippines advocacy group in 1988.

Among his ecclesiastical works are, "Eclesiastes" for choir and piano, his first large religious composition; "Misa" for unaccompanied choir; stage musicals like "Magnificat," “Birhen ng Caysasay" and, "Lorenzo;" and church songs such as or "I Believe in Peace," “The Prophet," “Asin ng Pamayanan," “Live Christ, Share Christ," and "Icthus" in St. John's Mass.

He won the Grand Prize award at the first Metro Manila Popular Music Festival for the song "Kay Ganda ng Ating Musika".