Greg received his Certified Naturalist credential through The Morton Arboretum in 1996 and has been teaching courses at the arboretum ever since. Active in ecological restoration, he has been a volunteer steward at several sites in the region. In 2013 he established True Nature Consulting to coach property owners in the care of their land. Since 2018 he has served as the Executive Director of the Kettle Moraine Land Trust in Walworth County, Wisconsin.