Perrin taught English literature at the Woman's College of the University of North Carolina from 1956 to 1959. He further studied at Cambridge University, where he received a Master's of Literature degree in 1958. He joined the Dartmouth faculty in 1959 as an instructor in English, reaching the rank of full professor by 1970. He specialized in teaching modern poetry, particularly that of Robert Frost. He was a Fulbright professor at Warsaw University in Poland in 1970, and was twice a Guggenheim Fellow. He joined Dartmouth's Environmental Studies Program in 1984 as an Adjunct Professor, teaching courses on a range of subjects.