McKeon received a B.A. in 1980 from Muhlenberg College cum laude in history and was awarded a J.D. in 1983 from the Seton Hall University School of Law. At graduation, he was the recipient of the Peter Rodino Law Society Outstanding Student Award. He then served as judicial clerk to Joseph M. Thuring, Superior Court of New Jersey, Hudson County and as a legislative aide to Representative Joseph Minish. McKeon is a former legislative counsel to Senator Richard Codey and counsel to the West Orange Board of Adjustment.