The Vestry along with the rector is responsible for the life of the parish and the management of its resources. The Vestry consists of the rector, senior and junior wardens (one-year positions, with junior warden becoming senior warden after two years), treasurer, assistant treasurer, clerk, and nine Vestry members, serving three-year terms. The Vestry meets on the third Tuesday of the month, year round, with the annual meeting in January. The Vestry members act as liaisons between the Vestry and the commissions and committees of the parish.

Additionally, St. Michael's elects representatives to attend the Episcopal Diocese of Massachusetts' annual convention and report on proceedings, and is a member of the North Shore Deanery.