John Wefing received his A.B. from St. Peter’s College in Jersey City, New Jersey in 1964, his J.D. from the Catholic University of America Columbus School of Law in 1967, and his LL.M. from New York University School of Law in 1971.

Wefing has practiced law and taught for over forty years. As a practicing lawyer, he served as Deputy Attorney General (temporary) for the New Jersey Attorney General’s Office for the summers of 1970 and 1971, as an attorney for the Kearny Planning Board from 1970 to 1989; as a clerk for Burgen County Grand Jury in the summer of 1973, and as of counsel at Waters, McPherson & McNeill from 1990 to present. Wefing has taught law at Seton Hall University School of Law since 1968 — first as an assistant professor, then an associate professor (1972-1975) before becoming a full professor of law (1975-2016). During that time, he also served as Associate Dean (1979 - 1982), Acting Dean (Spring 1988), and Richard J. Hughes Professor of Constitutional and Public Law (1997-2004). Since 2016, Wefing has been a Distinguished Professor of New Jersey Law and History emeritus at Seton Hall. Additionally, Wefing has been an adjunct professor at Rutgers; a visiting professor at Cardozo Law School, Catholic Law, and St. John's Law School; and a Teaching and Research Associate at Fordham Law School.

Wefing has also served as a member of various professional organizations and boards. He has been active in both the American Bar Association and the New Jersey State Bar Association — holding several positions in each. He’s also served on the board of Trustees for the New Jersey State Bar Association and the Board of Directors for Hudson County Legal Services. Throughout his career, Wefing has served as a member of the New Jersey Crime Prevention Advisory Council, the Supreme Court Task Force on Speedy Trials, the Ethics Committee for Hudson County, and the Governor’s Committee for Implementation of the New Criminal Code. Since 2011, Wefing has served on the Governor’s Council on Higher Education. Wefing’s exemplary work has been recognized through several awards and honors including: the Young Lawyers' Section of the New Jersey State Bar Association Award - Young Lawyer of the Year (1978), Professor of the Year Award (1987), Student Bar Association Award for Outstanding Dedication and Concern for Students (1988), Bishop Bernard J. McQuaid Medal for Distinguished Service to Seton Hall University (1988), Professor of the Year Award (2004), Thomas More Medal (2008), and Public Service Award (2009).