Following his graduation, Angelo worked as a teacher in the Saugus, Massachusetts school system, teaching history and law.

In 1978, he challenged thirty year incumbent Belden Bly for the 9th Essex District seat in the Massachusetts House of Representatives.

Angelo co-authored the Solid Waste Law which mandated that acid gas scrubbers be placed on the incinerator in Saugus.

Additionally, he pushed through laws on Acid Rain, Massachusetts State Revolving Fund, Wildlife Under the Wetlands, Hazardous Waste, Land Stamp, Tidelands, Open Space Acquisition, Underground Petroleum Storage, and the Cape Cod Commission.

Angelo also lobbied for and received state and federal funds to dredge the Saugus River, a project that had lingered since the 1960s.