David Ignatius Walsh was a United States politician from Massachusetts. A member of the Democratic Party, he served as the 46th Governor of Massachusetts before serving several terms in the United States Senate.
Born in Leominster, Massachusetts to Irish Catholic immigrants, Walsh practiced law in Boston after graduating from the Boston University School of Law. He served in the Massachusetts House of Representatives from 1900 to 1901, establishing a reputation as an anti-imperialist and isolationist. In 1912, he won election as the Lieutenant Governor of Massachusetts, becoming the state's first Democratic lieutenant governor in seventy years. He served as governor from 1914 to 1916 and led a successful effort to call for a state constitutional convention.
Walsh won election to the Senate in 1918, lost his re-election bid in 1924, and returned to the Senate with a victory in the 1926 special election to succeed Henry Cabot Lodge. Walsh became increasingly opposed to an activist government after 1924. He supported Al Smith over Franklin D. Roosevelt at the 1932 Democratic National Convention and gave lukewarm support to President Roosevelt's agenda.