 The Arthur L. Johnson High School Crusaders compete in the Union County Interscholastic Athletic Conference, which consists of public and parochial high schools covering Union County, operating under the jurisdiction of the New Jersey State Interscholastic Athletic Association (NJSIAA).With 570 students in grades 10–12, the school was classified by the NJSIAA for the 2015–16 school year as Central Jersey, Group II for most athletic competition purposes, which included schools with an enrollment of 498 to 750 students in that grade range.Before the 2010 realignment, the school had participated in the Mountain Valley Conference, which consisted of public and parochial high schools in Essex County and Union County.