The principal building on the Brooklandville campus is "Brooklandwood," a mansion built in 1793 by Charles Carroll of Carrollton (1737-1832), one of the signers of the Declaration of Independence.

[3] At the time of the school's founding in the mid-nineteenth century, boys studied Greek, Latin, and math.

Despite the school's small class sizes of roughly 70 students per class year, the school supports varsity teams in lacrosse, football, soccer, volleyball, cross-country, wrestling, basketball, ice hockey, squash, tennis, crew, golf, baseball.

[4][5][6] Spencer Horwitz played as a defenseman in hockey, and led the high school to two state championships.

[4][5][6] Since the start of varsity lacrosse interscholastic competition at St. Paul's in 1933, the Crusaders have won 25 titles in the old Maryland Scholastic Association (MSA) followed by the MIAA — more than any other team in the conference.

In 2010, St. Paul's won the conference championship, the 25th in school history, under head coach Rick Brocato.

St. Paul's has produced 12 C. Markland Kelly Award winners, which honors the top scholastic player in the state of Maryland each year.

Each year, the alumni association plays host to a number of events that bring alums back to campus.