His focus on insect life cycles and interactions with plants was influential in broadening American entomological studies beyond a narrow taxonomic approach.

[3] Harris became interested in entomology while still a student at Harvard where he attended the natural history lectures of William D. Peck.

His first publication, "Upon the Natural History of the Salt-marsh Caterpillar", appeared in 1823 in the Massachusetts Agricultural Repository.

While his published works focused on agricultural entomology, his prolific correspondence with other entomologists was more often related to insect classification and other technical aspects.

Harris' study of insects was a result of his having interacted with William D. Peck while a student at Harvard.