He is known for his work in two overlapping fields, classical American philosophy and semiotics. Colapietro is the author of Peirce's Approach to the Self: A Semiotic Perspective on Human Subjectivity (SUNY Press, 1989) and has published numerous articles in such journals as The Journal of Philosophy, The Transactions of the Charles S. Peirce Society, The Journal of Speculative Philosophy, and The Bucknell Review.