 He was rooted in his family's business, the House of Diggs, which at one time was said to be Michigan's largest funeral home.In 1954, Diggs defeated incumbent U.S. Representative George D. O'Brien in the Democratic Party primary elections for Michigan's 13th congressional district.He went on to win the general election to the 84th Congress and was subsequently re-elected to the next twelve Congresses, serving from January 3, 1955, until his resignation June 3, 1980.