Nedzi was elected as a Democrat from Michigan's 1st congressional district to the 87th United States Congress in a special election in 1961 to fill the vacancy caused by the resignation of United States Representative Thaddeus M. Machrowicz. He was re-elected in the 1962 election and two years later he was elected from the 14th district and every two years after that until he declined to seek re-election in the 1980 election. In all, he served from November 7, 1961 to January 3, 1981.