The school's student body was 43.5% (91) White, 35.9% (75) Hispanic, 10.5% (22) two or more races, 5.3% (11) Black, 4.3% (9) Asian and 0.5% (1) Native Hawaiian / Pacific Islander.

[9][10][11] Prior to the NJSIAA's realignment that took effect in the fall of 2010, St. Mary was a member of the Bergen County Scholastic League (BCSL).

[15] Down by five points in the last minute of play, the 1935 team won the Group II (since recategorized as Non-Public A) state title with a 32–31 win against St. Peter's in overtime.

[20] The 1980 team won the Parochial B North state title with a 6–0 victory against Pope John XXIII after scoring a touchdown in double overtime to finish the season with an 8-0-1 record.

[22] The softball team won the Non-Public B state championship in 1998 to finish the season with a 31–2 record after defeating St. Joseph High School by a score of 3–2 in the tournament final in extra innings.