As a composer and arranger, he has written in most genres of music, including jazz, funk, Top 40, country, classical, new age, etc. Some of his writing is for commercial radio and television commercials in both local and regional markets. Other times it is work-for-hire in collaboration with a lyricist or songwriter in need of musical direction. Much of the jazz composing has appeared on recordings as a member of bands including Time Out, Cathy Morris, Small Talk, the Carter-Markiewicz Quartet, and the Icarus Ensemble.

For the last several years, Gary has focused on writing for various chamber ensembles including mallet percussion, string trio, unaccompanied cello, brass quintet, jazz combos and string orchestra. His "Mongrel No. 1" for solo piano was premiered by Stephen Beus, winner of the 2006 American Pianist Association competition, held in Indianapolis every two years.