After World War II, the school added a gymnasium and classrooms to its building on Cumberland Street, to accommodate enrollment that rose as high as 300 during the 1950s, and reached 700 in the 1970s.

[9] In the 2000s, the Roman Catholic Diocese of Camden explored possibilities to move the school to Gloucester County, New Jersey.

[20] Gloucester Catholic's first state championship was delivered by the 1964 basketball team, who won the Group B title in Atlantic City Convention Hall.

[23] The team won the Group I state championship in 1976 (defeating runner-up St. Anthony High School in the tournament final), 1977 (vs.

[27] A last-second defensive play helped the team repeat as Group I champion in 1978 with a 70–68 win against Mother Seton in the playoff finals.

[32] The 2000 team beat Seton Hall Prep by a score of 13–4 in the Parochial A championship game to finish with a 33–1 mark for the year.

[34][35] The 2003 team finished the season with a record of 25-5 after a one-hitter in the Parochial B championship game against St. Mary of Rutherford, which they won by a score of 3–0.

The 2017 team defeated Newark Academy by a score of 15–5 in the playoff final of the Non-Public B tournament, to win the program's 18th state title.

Under head coach Al Radano, the 1980 squad posted a perfect 24–0 record to win the New Jersey Parochial B state championship.

In 2000, Gloucester Catholic was crowned national champions after winning a state title and posting a 33-1 overall record under head coach Dennis Barth.

Led by Rucci, a catcher, along with pitcher Greg Burke, the Rams defeated some of the best teams in the state and the country that season.

[40] The team won the Parochial South B state sectional championship in 2001 with a 1–0 win over St. Joseph High School in the tournament final.

[46] In the 2010 Non-Public B championship game, the team finished the season with a 23–6 record as they defeated Immaculate Conception of Lodi by a score of 11–1.

[47] The team won its second consecutive Non-Public B state championship in 2011 with a 4–0 win against Morris Catholic High School in the tournament final, finishing the season with a 21–4 record.

[49] The girls' soccer team won the 2000 Parochial South B state sectional championship, defeating Wildwood Catholic High School 5–0 in the tournament final.

[50] In 2007, the team won the Non-Public South A state sectional championship with a 3–0 win over Holy Spirit High School in the tournament final.

[56] The 2006 boys' tennis team won the Non-Public, South B state sectional championship with a 3–2 win against Bishop Eustace.