In 1994 Nakano joined the New Frontier Party and served as the Chair of the Policy Inquiry Commission. Upon the collapse of the party, Nakano formed the New Fraternity Party, which eventually merged with other liberal parties to form the Democratic Party of Japan. He currently represents the Osaka 8 electoral district.
Note: As part of Diet custom, the Speaker and Vice-Speaker of the House must formally secede from their party. For this reason, Nakano is sometimes referred to as an independent in official Diet information. In practice he remains a member of the DPJ.