Julian Barker started his training in herbal medicine in North and Central America, before returning to Britain as an apprentice herb-grower at Suffolk Herbs while studying concurrently on NIMH's tutorial course, at which point he joined the first cohort at the School of Herbal Medicine. In 1983, he opened a clinic in Brighton offering acupuncture, herbal medicine, homeopathy, and osteopathy but recently has upsized to a single practice.

Teaching botany at the School of Herbal Medicine for over twenty years, Julian supervised BSc dissertations and taught philosophy on the MSc course in herbal medicine at the University of East London. Since 1998 he has worked in Paris and has studied in London with Dr. Jean-Claude Lapraz on the application of medicinal plants along Endobiogenic lines.

He is a fellow of the Linnaean Society and the National Institute of Medical Herbalists, and a member of the College of Practicing Phytotherapists.