Michael J. Bradley was born in Philadelphia, PA. He was engaged as a telegrapher from 1914 to 1917. During the First World War, Bradley served overseas as a chief radio electrician in the United States Navy from 1917 to 1919. Bradley engaged in the security and brokerage business in Philadelphia,from 1921 to 1935, and served as the deputy insurance commissioner of Pennsylvania from 1935 to 1937. Bradley was an unsuccessful candidate for election in 1934.
Bradley was elected as a Democrat to the 75th Congress and to the four succeeding Congresses. He was not a candidate for renomination in 1946. After his time in Congress, he served as chairman of the Democratic county executive committee of Philadelphia from 1946 to 1948, collector of customs for district No. 11, Port of Philadelphia, 1948-1953; deputy managing director, city of Philadelphia, 1953-1955; member of Pennsylvania Navigation Commission for the Delaware River, 1954-1964; chairman, Board of Fair Labor Standards, city of Philadelphia, 1954-1962.
He became a member of Board of Revision of Taxes, city of Philadelphia, April 1955; retired in 1976; resided in Philadelphia, Pa., where he died , 1979; interment in Holy Cross Cemetery, Yeadon, PA.