Grillo served as a visiting artist at various institutions such as University of California, Berkeley, Studio School of New York City and Southern Illinois University at Carbondale. He was an instructor in the mid-60s at Pratt Institute and from 1967-1991 taught at the University of Massachusetts at Amherst. Currently he lives and works in Provincetown, MA.

Grillo has and continues to exhibit widely. During the 1950’s he had shows at Tanager Gallery, Tibor de Nagy Gallery and Berta Schaefer Gallery. He was included in four of the Stable Gallery Annuals and showed at the Whitney Museum of American Art. Other exhibitions include shows at the Howard Wise Gallery in New York, the San Francisco Museum of Art, Yale University, The Guggenheim Museum, The Brooklyn Museum, Grace Borgenicht Gallery, Carlson Gallery, Aaron Gallery and Katarina Rich Perlow Gallery. His work is part of the collections of various museums such as: the Butler Institute of American Art, Los Angeles County Museum of Art, Metropolitan Museum of Art, Guggenheim Museum, Brooklyn Museum, the Whitney Museum of American Art and many others.