In 1952, Grasso was elected to the Connecticut House of Representatives, and served until 1957. She became first woman to be elected floor leader of the House in 1955. In 1958 she was elected Secretary of State of Connecticut and was re-elected in 1962 and 1966. She was the first woman to chair the Democratic State Platform Committee and served from 1956 to 1968. She served as a member of the Platform Drafting Committee for the 1960Democratic National Convention. She was the co-chairperson for the Resolutions Committee for the Democratic National Conventions of 1964 and 1968. In 1970 she was elected as a Democratic representive to the 92nd Congress, and won reelection in 1972.
In 1974 Grasso did not run for reelection to Congress, instead running for the Connecticut governorship, and won. She began her first term in 1975 and was elected to a second term in 1978.
After attending St. Mary's School in Windsor Locks, and then the Chaffee School in Windsor, GovernorGrasso went on to Mount Holyoke College, in South Hadley, Massachusetts, where she was awarded her BA in 1940 and her MA in 1942.
In 1970 she was elected to the House of Representatives in the 92ndCongress as a Democrat representing Connecticut, and in 1972 she was re-elected, and so served Connecticut from January 3, 1971 through January 3, 1975 in the House.
In 1974Grasso was not a candidate for re-election to Congress.
After attending St. Mary's School in Windsor Locks, and then the Chaffee School in Windsor, Grasso went on to Mount Holyoke College, in South Hadley, Massachusetts, where she was awarded her BA in 1940 and her MA in 1942.