Constructed on a site covering 25 acres (10 ha) and including 94,000 square feet (8,700 m2) of space for classes and other facilities, the school opened in September 1956 and was named for a longtime county superintendent who was a leading advocate for the establishment of a regional school district.

[9] In April 1957, voters approved a $3.8 million bond referendum that included funds for an addition at Johnson.

[11] On May 4, 1971, voters approved a $4.7 million bond referendum to expand and renovate each school in the district.

[13][14] Amid conflict between the constituent municipalities about financing a district described as "the highest-spending regional high school in the state" and anger from residents impacted by the closure of David Brearley High School, a referendum was held in May 1996 in which voters approved a proposal to breakup the regional district.

[25] The Arthur L. Johnson High School Crusaders[3] compete in the Union County Interscholastic Athletic Conference, which is comprised of public and private high schools in Union County, and was established following a reorganization of spots leagues in Northern New Jersey under the jurisdiction of the New Jersey State Interscholastic Athletic Association (NJSIAA).

[28] The football team competes in Division 2B of the Big Central Football Conference, which includes 60 public and private high schools in Middlesex, Hunterdon, Somerset, Union and Warren counties, which are broken down into 10 divisions by size and location.

[35] The ice hockey team won the McMullen Cup in 2020, defeating Frisch School by a score of 7–3 in the tournament final.