In 1970, Biden ran for the 4th District Seat on the New Castle County Council on a liberal platform that included support for public housing in the suburbs. The seat had been held by Republican Henry R. Folsom, who was running in the 5th District following a reapportionment of council districts. Biden won the general election, and took office on January 5, 1971. He served until January 1, 1973, and was succeeded by Democrat Francis R. Swift. During his time on the county council, Biden opposed large highway projects, which he argued might disrupt Wilmington neighborhoods.