While at Rider College in 1972-1973, John was hired by the Office of Public Defender in Trenton as a part time assistant investigator. On graduating from Vermont law School, he was accepted as the Law Clerk to the Honorable Herman Belopolsky, J.C.S., Honorable Harold B. Wells, III, A.J.S.C. and Honorable W. Thomas McGann, J.C.S.
On passing the Bar in New Jersey in 1976, he joined the firm of Mathews and Sitzler, as an associate and was made partner the following year.
In 1979, John became Solicitor for the Wrightstown Borough Planning Board as well as Municipal Prosecutor for Pemberton Township. Over the next few years John became a Solicitor for the Delran Township Planning Board as well as Municipal Prosecutor for many municipalities including Hainesport, Cinnaminson, New Hanover, and Springfield.
In 1990, he and his father, John O. Sitzler, Jr. formed the partnership of Sitzler and Sitzler and in 1995 became the Sole Proprietor of Sitzler and Sitzler when his father became of counsel to the firm.
In 2000, John began teaching as an adjunct Professor of Law, at Widener University School of Law on the Wilmington Delaware Campus and teaches Alcohol, Vehicle, and the Law, one of the most popular courses at Widener.
In August of 2007, 2008, 2009 and again in 2010, John was nominated in the SJ Magazine, by his peers, to be the top attorney to work with on DWI defenses cases. South Jersey Magazine noted that John S. Sitzler was voted Top DUI attorney by the public for 2010.
