[11] America's entry into World War II, and the resulting increase in government spending, helped revive the school's fortunes.

[12] Under headmaster Charles F. Hamilton (h. 1942–71), enrollment and Upper School day student tuition nearly quadrupled.

[17] The school maintains a small five-day boarding program for up to 27 local students who commute home on weekends.

Reginald Howe had previously coached the Harvard varsity crew, and he "employed as faculty young men, often just out of college, who had distinguished themselves athletically as well as academically.

"[23] As of the 2020 Tokyo Olympics, the school has educated 16 Olympians, including hockey gold medalists Bill and Bob Cleary.

[24] Today, Belmont Hill offers 16 interscholastic sports and 58 teams, and claims that "virtually all teachers are coaches.

[43] The music program includes jazz and rock bands, an orchestra, and multiple singing groups.

The school holds an annual week-long spring break trip to different regions throughout the United States, including California, Alabama, and Florida.

[47] Belmont Hill participates in a University of Pennsylvania-led research consortium to "systematically mobilize student insights and voices to improve school culture, policy and practice.