Grossinger was born and raised in New York City, attended Horace Mann School, Amherst College, and the University of Michigan, earning a B.A. in English at Amherst and a Ph.D. in anthropology at Michigan. With his wife (then girlfriend at Smith College) Lindy Hough, he founded the journal Io in 1964, then founded North Atlantic Books in Vermont in 1974. Between 1970 and 1972 he taught anthropology at the University of Maine, Portland-Gorham, now the University of Southern Maine, and between 1972 and 1977 he taught interdisciplinary studies (including alchemy, Melville, Classical Greek, Jungian psychology, and ethnoastronomy) at Goddard College in Plainfield, Vermont. An ethnographer and self-described psychospiritual explorer as well as a writer and publisher, he has "studied" or "trained" in homeopathic medicine, somatic theory, t'ai chi ch'uan, craniosacral therapy, qigong, Breema, yoga, and something called "psychic healing". His brother was Jonathan Towers, a poet who committed suicide in 2005. His daughter is filmmaker, author and performance artist Miranda July.