For 26 years, Callicott lived and taught in the northern reaches of Wisconsin's sand counties, located on the Wisconsin River, just ninety miles from Aldo Leopold's storied shack and John Muir's first homestead on Fountain Lake, the region that stirred the souls of two very influential environmental thinkers. Callicott writes that “the landscape that had helped shape and inspire the nascent evolutionary-ecological thought of the youthful Muir and that of the mature Leopold was the perfect setting for (me) to inaugurate (my) life-long vocation as a founder of academic environmental philosophy.” In 1995, he joined the Department of Philosophy and Religion Studies at the University of North Texas in Denton. The first graduate program in environmental philosophy had been launched at UNT in 1990 under the aegis of Eugene C. Hargrove, then department chair and founding editor of the journal "Environmental Ethics". The addition of Callicott's expertise helped cement its standing as the world's leading program in the field.