Mike Rivera was born and raised in Rochester, N.Y., in a union household. He began working with the City of Rochester, Local 1635 in 1993 as a laborer in the Parks Department. Two years later, he began working for the Public Works Department as an operation worker in street construction and in 1999, became a sanitation worker in the Refuse Department. In 2011, Rivera became a union steward in the Solid Waste Department and continues his union involvement to this day. He was elected vice president of Local 1635 five years later. In 2017, he was elected to the Council 66 Executive Board as a member-at-large. In 2021, Rivera was elected president of Local 1635. He presently serves as president of Local 1635 and as the vice president of the Council 66 Executive Board — the first Puerto Rican to serve in both those roles. Rivera helps represent over 8,500 union members across New York state.
In 2024, Rivera was elected to the AFSCME International Executive Board and now also serves as an International vice president.