Claim: Democratic Richard J. Daley won the 1955 Chicago mayoral election and was chairman of the Cook County Democratic Party Central Committee.
Evidence: Richard Joseph Daley (May 15, 1902 – December 20, 1976) was an American politician who served as the Mayor of Chicago from 1955 and the chairman of the Cook County Democratic Party Central Committee from 1953 until his death. 
In the Chicago mayoral election of 1955, Richard J. Daley was elected to his first term as mayor by a ten-point margin. Daley became chairman of the Central Committee of the Cook County Democratic Party, i.e. boss of the political machine, in 1953.