His work as a film composer includes his collaborations with director John Curran on the biopic Chappaquiddick, starring Kate Mara and Jason Clarke, and Tracks which featured Mia Wasikowska and Adam Driver. Other notable films include Them That Follow, (Olivia Coleman). 10,000 Saints (Ethan Hawke), Resilience, Tater Tot & Patton, Seed, Roadside Picnic, The Grizzlies, Red Knot, Young Lakota.
Stevenson has performed all over the world as a solo artist and with bands. In 2009 he began offering music meditation hikes at Wanderlust where he leads intimate audiences on a hike then improvises music in nature.
Garth attended Berklee College of Music on a full scholarship. He is the recipient of the International Society of Bassists composition competition, the Henry Mancini fellowship by ASCAP, and a four-time recipient of Canada Council grants.