[2] Other founders included Harvard professor Roger Bigelow Merriman and Charles Slattery, the acting (and future) Bishop of Massachusetts.

[1] The school opened on September 29, 1927, with fourteen boys in the first and second forms (seventh and eighth grades), two masters, a headmaster and headmistress, and one dormitory.

The school added one form (grade) each year thereafter until it comprised grades 7–12, denoted by the British educational notations, Forms I, II, III, IV, V, and VI, respectively.

The school started admitting day students in the early 1950s and became co-educational in 1979.

[5][6] In the 2022-23 school year, Brooks enrolled 353 students (76 freshmen, 83 sophomores, 92 juniors, and 102 seniors).