Millard Evelyn Tydings was born in Havre de Grace, Maryland, on April 6, 1890, the son of Millard F. and Mary B. (O'Neill) Tydings. He graduated early from high school and went on to the Maryland Agricultural College (later the University of Maryland) where he was well known for his debating skills. He earned his B. S. in Engineering in 1910, and then received his law degree from the University of Maryland law school in 1913. He was again affiliated with the university years later, as a member of the Board of Regents from 1946 to 1951.
Tydings was admitted to the Maryland bar immediately after receiving his law degree in 1913 and practiced for two years before his election to the Maryland House of Delegates in 1915. In 1916, Tydings enlisted as a private in the Army and served overseas in the 29th Division, later commanding the 111th Machine Gun Battalion. He was awarded the Distinguished Service Medal and a 29th Division Citation for Gallantry. Tydings returned from the war with the rank of lieutenant colonel and was named Speaker of the Maryland House of Delegates. He served in that capacity from 1919 to 1921. He then served in the Maryland Senate until 1923, when he was elected to the U. S. House of Representatives. Four years later Tydings was elected to the U. S. Senate, where he served continuously until 1951.
During these twenty-four years, he became a so-called "Titan" in the Senate. As a conservative Democrat, Tydings achieved prominence through his willingness to engage major figures on the national scene, from Franklin Delano Roosevelt to Joseph McCarthy, in debate and controversy.
Tydings' years in the Senate were also marked by strong opinions, controversy, and confrontations with several powerful figures. In the wake of war he sponsored a bill calling for world disarmament. In 1930, he published Before and After Prohibition, an account of the failure of prohibition and his recommendations for liquor control. Counter-Attack, in which Tydings enumerated his views on the Depression, its international causes and curses, was published three years later. In strong opposition to Franklin Delano Roosevelt's economic strategy and deficit spending, Tydings proposed a constitutional amendment mandating a balanced budget. He also opposed Roosevelt's attempts at court-packing (reorganization of the federal judiciary) in 1937 and 1938. Tydings' most valuable and remembered contributions, however, came out of his participation on and chairmanship of various committees, including the committees on Foreign Affairs and Relations, Armed Services, and Territorial and Insular Possessions. As a member of the latter committee, Tydings was intimately involved in Philippine affairs and co-authored the 1934 Tydings-McDuffie Act that called for Philippine independence. And when Senator Joseph McCarthy's charges of Communist infiltration of the State Department became the responsibility of the Committee on Foreign Relations, Tydings chaired the investigating subcommittee. His behavior and position as a member of this committee both proved Tydings' worth as a leader and conscientious politician and cost him his Senate seat in the 1950 election.
Even before McCarthy arrived on the scene, Maryland had a long history of anti-Communism and had the strongest loyalty oath in the nation on its law books. Tydings' moderate approach to the McCarthy hearings and his refusal to give in to popular hysteria alienated him from many of his Maryland constituents. The 1950 Senatorial election in Maryland involved a smear campaign against Tydings. A post-election investigation revealed that McCarthy had played a role in funding opposition to Tydings and had helped to lead to his defeat.
After his retirement from the Senate, Tydings returned to membership and practice in a law firm. He ran once more for political office in 1956 but was forced to withdraw from the race due to ill health. On February 9, 1961, he died at his home, "Oakington," near Havre de Grace, Maryland. He was survived by his wife, Eleanor Davies Cheesborough Tydings, whom he married in 1935, and his adopted son, the future Senator Joseph D. Tydings.