"Not for oneself, but for all," is the translation of the school's motto - Non Sibi Sed Cunctis - and the founding principle behind the Community Service Program at Millbrook; since 1931, students have worked together in operating services which support almost every facet of school life.

Community Service periods are included in the formal class schedule four times per week, but since students often choose their services based on their individual interests, they may find themselves devoting extra time to their volunteer work. From managing money in the Strong Box (the school bank), to caring for the animals at the zoo, to working on the library's computers, all Millbrook students learn to be actively involved in their community.

The Community Service Cup is awarded at commencement each year to a member of the graduating class who has most faithfully exemplified the school's motto. This recognition is a strong indication of how highly Millbrook values this program.