His father, Sherlon Hilliard (of Irish and English descent), possessed a fine tenor voice and was a popular gospel-style singer with their county Protestant Church of the Nazarene congregations.
They later both shared another influential music teacher, Virgil Spurlin, during their years together in the Hot Springs High School Band.
In 1964 Hilliard played at all-state band under W. Francis McBeth, who would later become his first composition teacher for four years at Ouachita Baptist University, Arkadelphia, Arkansas.
1, "Okeanos", was premiered in 2000 by pianist Eric Ruple with the James Madison University Wind Symphony at the College Band Directors National Association Conference.
Hilliard's second piano concerto was commissioned by the Staunton Music Festival (Virginia) and had its premiere there at the Blackfriars Playhouse in 2004, with the composer conducting.
In 2006, the James Madison University Wind Symphony premiered his "Variations on a Theme from 'L'oiseau de feu'".
In 1995, Hilliard was given an Artistic Fellow residency grant by the Japan Foundation in Tokyo, studying shakuhachi with Christopher Yohmei Blasdel and gagaku in Nara at the Kasuga Shrine.
During his years there, in addition to studying Japanese traditional music, he practiced Zen Buddhism (zazen in Nara).
In addition, he has attended masterclasses with Ezra Laderman, Alan Hovhaness, Włodzimierz Kotoński, George Crumb, Homer Keller, Milton Babbitt, Ben Johnston, Joseph Schwantner, Paul Creston and Olivier Messiaen.
Numbered among his students is Joel McNeely, a noted film composer for Disney studios and George Lucas.
Other students include Steve Van Dam (founder of the band Everything), David Castle (songwriter), Terry Vosbein (composer/arranger/educator), Larry Clark (Vice Pres., Editor-in-Chief, Carl Fischer Music), Evan Duffy, Matthew Labarge, and Butch Taylor (formerly of the Dave Matthews Band).
In 2013 the university sponsored a special celebratory concert in his honor which was attended by 30 former composition students, and performed mostly by JMU current music majors.