In answer to a need for an all boy’s Catholic high school in the Waterbury area, ground was broken for Holy Cross High School on March 26, 1967. The first freshman class of three hundred twenty five (325) students was admitted on April 13, 1967 by the late Archbishop John F. Whealon.
Holy Cross High School was initially staffed by ten Holy Cross Brothers from the Eastern Province of Brothers of the Congregation of Holy Cross. The enrollment reached one thousand by 1974 and the faculty and staff grew to over fifty including priests, brothers and lay teachers.
In September, 1975 a merger was effected between Holy Cross High School and Waterbury Catholic High School for girls, when the latter school, conducted by the Sisters of the Congregation de Notre Dame, closed its doors.
The merger of these two schools took place under the direction of Brother Francis Leary, C.S.C., the principal of Holy Cross High School and Sister Joanne Drinane, C.N.D., principal of Waterbury Catholic High School. The new facilities of the coeducational Holy Cross High School were blessed and rededicated by Bishop Joseph F. Donnelly, on November 26, 1975.