[7] The Plainfield High School Cardinals[2] 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 sports leagues in Northern New Jersey by the New Jersey State Interscholastic Athletic Association (NJSIAA).

[20] Down by nine points early in the fourth quarter of the championship game, the 1972 team came back to tie Neptune in regulation and win the Group IV title 75-72 in overtime.

[21] The team won the 2004 North II, Group IV state sectional championship, defeating Elizabeth High School 47–42 in the final.

[22] The 2012 team came back from a five-point deficit at the half to win the Group III title with a 58–48 defeat of Neptune in the championship game played at the Pine Belt Arena.

Hall of Fame coach Bob Hurley called Plainfield, "the best basketball community in New Jersey.

"[24] The boys' track team won the Group IV state indoor relay championship in 1980 and 1981 (as co-champion with Trenton Central High School).

[25] The girls' outdoor track and field team won the Group IV state championship in 1982, 1985, 1986, 1991 and 1993.