Neisser is sometimes called the father of cognitive psychology due to a book he published in 1967, titled Cognitive Psychology. The field was already well under way by that date, but Cognitive Psychology did much to make the theoretical foundations and the experimental framework explicit. That served both to define the field, and to help train new students. (It's less often mentioned that Neisser repudiated this framework in a 1976 books, Cognition and Reality, in which he adopted a more Gibsonian view of perception.)
Neisser was not just a theoretician, but a gifted experimentalist. Among other important findings, he conducted an experiment showing the people focusing on a complex video scene failed to notice a woman with an open umbrella traverse the scene, anticipating Simon & Chabris's now-famous gorilla video. In memory research, Neisser did important work in showing that “flashbulb” memories, although held with great confidence, are not terrible accurate.
Neisser spent most of his career at Cornell, and died in Ithaca.