Theodore Roosevelt McKeldin was born in south Baltimore on November 20, 1900. His father, James A. McKeldin, was a Scots Irish stonecutter from Baltimore, who later became a City policeman. His grandfather, also a stonecutter, was from Belfast and may have been the son of Joseph McKeldin, also from Belfast, listed in British Aliens in the U.S. during the War of 1812, compiled by Kenneth Scott and published by the Genealogical Publishing Company of Baltimore, 1979. Edward Hazelton McKeldin, his grandfather, was killed fighting with the Union Army at the Battle of the Monocacy, Frederick County, Maryland, on July 9, 1864, and is buried at the National Cemetery at Antietam. His mother, Dora Greif McKeldin, was the daughter of German immigrants. McKeldin married Honolulu Claire Manzer in 1935; they had two children, Theodore Roosevelt, Jr., and Clara Whitney.
In 1925, McKeldin graduated from the University of Maryland Law School with a bachelor's degree in law. He later studied economics at Johns Hopkins University. In 1927, he established a law practice with Charles E. Moylan and Michael Paul Smith. McKeldin soon interrupted his practice to accept a political appointment as executive secretary to Mayor William F. Broening of Baltimore, whom he supported in the 1927 election. He returned to his private law practice in 1931.
Eight years later, McKeldin ran unsuccessfully for mayor of Baltimore, losing to Howard W. Jackson. He suffered another setback in 1942 when he opposed Herbert R. O'Conor in the Maryland gubernatorial race. The following year, however, he defeated Jackson in the race for mayor of Baltimore.
McKeldin served as mayor of Baltimore from 1943 to 1947. Among the achievements of his administration were the completion of Friendship Municipal Airport (now Baltimore Washington International Airport); the construction of a new civic center; and the management of Baltimore's wartime economy. He also appointed George McMechen to the Baltimore School Board, the first African American to hold this position, which earned McKeldin a reputation as an advocate of racial integration and civil rights.
In 1946, McKeldin again lost his bid for the governorship--this time to William Preston Lane, Jr. Four years later, however, McKeldin faced Lane again and successfully used an anti sales tax platform to defeat him. As governor of Maryland from 1951 to 1959, McKeldin launched a vigorous program of reform and reconstruction, which included the Sobeloff Commission on State Government and Bureaucratic Administration and a twelve year plan for state highway construction. He achieved nationwide prominence at the 1952 Republican Convention when he was selected to nominate Dwight D. Eisenhower for the presidency.
In 1959, McKeldin ran again for mayor of Baltimore, losing this time to Harold Grady. He retired to private law practice with his associate, William Adelson. In 1963 he returned to public life, narrowly defeating Philip H. Goodman in the race for mayor of Baltimore.
During McKeldin's second term as mayor, which lasted from 1963 to 1967, he embarked upon a wide ranging program of urban renewal, which included the beginnings of the redevelopment of Baltimore's Inner Harbor, construction of a new municipal building, and the planned elimination of the city's slums. However, this urban renewal program ultimately displaced over 800 households and around 3,000 residents of predominantly Black neighborhoods due to the destruction of hundreds of homes. Businesses were also displaced resulting in the loss of over 500 jobs in the community and causing barriers to daily life for residents without cars due to this urban renewal program headed by McKeldin.McKeldin also continued to support the civil rights movement by hosting a meeting of the Congress of Racial Equality in July 1966.
After his retirement from the Baltimore political scene, McKeldin's interests and activities remained varied. In 1967, President Johnson appointed him to a panel of American observers chosen to supervise the September elections in South Vietnam. In 1968, McKeldin testified in opposition to capital punishment before the United States Congress. He was a vocal supporter of the state of Israel, founder and president of the America-Israel Society, and he assisted with the sale of Israeli war bonds throughout the 1960s.
Among his many publications were The Art of Eloquence (1952), co authored with John C. Krantz; Washington Bowed (1956), which was reprinted as Hats for General Washington in 1973; and No Mean City: An Inquiry in Civic Greatness (1964).
McKeldin retired in 1968 and died on August 10, 1974, at the age of seventy-three.