After graduating from Tokyo Imperial University in 1937, Tanaka joined the South Manchuria Railway.

He later served as a researcher in the Planning Agency, a bureaucrat in the Ministry of Munitions, and a secretary to Minister of Agriculture and Commerce Shimada Toshio during the Koiso Cabinet.

Following the end of World War II, Tanaka was appointed as a secretary to Minister of Commerce and Industry Ogasawara Mikio in the Shidehara Cabinet.

[1] In 1953, Tanaka resigned as governor midway through his second term to run as an independent candidate in the 26th House of Representatives election.

He later followed Kishi Nobusuke, his senior from the same prefecture, into the newly formed Japan Democratic Party.