Alan Cohen grew up in Pennsylvania and North Carolina. After earning a degree in nuclear engineering at North Carolina State University and working at Argonne National Laboratory, doctoral program study began in thermodynamics at Northwestern University. In 1969, he began photographing and eventually left the sciences to study photography. As a graduate student at the Illinois Institute of Technology's Institute of Design, he studied with Aaron Siskind, Arthur Siegel, Garry Winogrand, Charles Swedlund, Ken Josephson, and Joe Jachna. He was awarded a M.Sc. Photography degree in 1972.
Married to Susan Walsh, Cohen lives in Chicago and was a member of the visiting faculty at Columbia College Chicago's Department Of Photography and The School for New Learning at DePaul University. Cohen was an Adjunct Full Professor in the Art History, Theory, Criticism Department at the School of the Art Institute of Chicago from 1987 until 2012.