Islewilde was founded in 1992 by UMO, a Vashon Island-based physical theater troupe, who patterned Islewilde loosely after Vermont's Bread and Puppet Theater. The philosophy behind the festival is that communal creation of art helps to foster a vibrant community. "Community Creating Art Creating Community" is a slogan of the group. UMO spent four years actively organizing Islewilde before handing it off to members of the Vashon arts community, who have run the festival since with limited continuing involvement from its founders.