Marcus A. Coolidge (October 6, 1865 - January 23, 1947) was a Democratic Senator of Massachusetts from March 4, 1931 to January 3, 1937.
Coolidge was born in Westminster, Massachusetts, son of Frederick Spaulding Coolidge. After attending public schools and Bryant & Stratton Commercial College at its former Boston, Massachusetts campus, Coolidge worked with his father's company in manufacturing chairs and rattan. He later worked in the contracting business, building street railways, water works, and bridges.
In 1916, Coolidge was elected mayor of Fitchburg, Massachusetts. In 1919, President Woodrow Wilson appointed Coolidge as special envoy to Poland to represent the Peace Commission. He became chairman of the Democratic State convention in 1920. Coolidge also served as trustee and president of the Cushing Academy at Ashburnham, Massachusetts.
After being elected to the United States Senate in 1931, Coolidge served as chairman of the Committee on Immigration for the Seventy-third and Seventy-fourth Congresses, but was not a candidate for renomination in 1936.
After leaving the Senate, Coolidge returned to Fitchburg and his former business pursuits. He died at Miami Beach, Florida in 1947, and is interned in Mount Pleasant Cemetery in Westminster, Massachusetts.