The school's student body was 59.2% (271) White, 16.4% (75) Hispanic, 12.2% (56) Black, 9.2% (42) two or more races, 2.6% (12) Asian and 0.4% (2) American Indian / Alaska Native.

[9] Saint Joseph Regional offers courses in English, world/US history, science, foreign language, mathematics, theology, and a number of electives, most with accelerated and honor levels.

[citation needed] The Saint Joseph Regional High School Green Knights[3] participate in the United Division of the Big North Conference, a super conference comprised of public and private high schools in Bergen and Passaic counties that was established as part of a realignment of sports leagues in Northern New Jersey and operates under the supervision of the New Jersey State Interscholastic Athletic Association.

[17] The Green Knights have achieved league, county and state titles in football, baseball, basketball, wrestling, golf, ice hockey, and winter and spring track and field athletics in the last two decades.

[citation needed] SJR varsity fall sports include football, cross country, and soccer.

[18] The SJR varsity football team had a streak of seven Non-Public Group III titles through the 2005 season, a run ended with a 35-28 loss to Holy Cross High School on a touchdown scored in the final minute of the first round of the 2006 playoffs.

[24] The 1988 team finished the season with a 10-1 record after winning the Non-Public A North sectional title after a 29-18 victory against Delbarton School in the championship game.

[25] A 32-26 win in the 1995 Parochial Group III championship game at Giants Stadium against DePaul Catholic High School gave the team an 11-0 record for the season.

[26] The team won the 2000 Parochial Group III title in 2000 with a 54-29 win against Pope John XXIII Regional High School in the finals.

[27] The 2001 team won the Parochial Group III title with a 17-9 victory in the tournament final against Immaculata High School.

[28] The 2008 team finished with an 11–1 record and won against Immaculate by a score of 27–6 in the Non-Public Group III state championship game.

Don Bosco leads the rivalry with a 30–23 overall record as of 2017, which includes periods in the 1990s and 2010s when the two schools played each other on Thanksgiving.

[36] In 2010, SJR hockey, who entered the NJTCC Cup as the lowest seed, upset top-seeded Passaic Valley High School and DePaul en route to the championship on February 28.

In the winter of 2013, the SJR Ice Hockey team won their fourth league championship appearance in a row.

In 2015, the team reached the state quarterfinals after upsetting the #2 ranked Don Bosco Preparatory High School in the Round of 32.

The Green Knight Hockey Team reached the state quarterfinals once again in 2016, losing to Pope John XXIII Regional High School in overtime.

[citation needed] In 2025, the team won their first Bergen County championship after defeating Don Bosco Preparatory High School by a score of 2–0 in the tournament final.

[citation needed] SJR offers five varsity spring sports including baseball, golf, lacrosse, tennis, and track and field.

West Side Story also received the 2008 Showstopper Runner-Up Award for best musical in the country by USA Weekend.

SJR presented Brighton Beach Memoirs as their spring drama, garnering 11 Montclair Theatre Night Award Nominations, including Best Overall Production, and two wins.

St. Joes has a TV studio, WSJR, that runs on a closed circuit system on every school day from 8:15am to 8:24am.