Ms Tanaka, 57, is well known for her non-conformist approach and has been voted Japan's most popular politician.
Ms Tanaka, 57, is well known for her non-conformist approach and has been voted Japan's most popular politician.
She has won popularity by openly criticising other political leaders and adopting a relaxed public image. She is happy to chat to the public, often wearing T-shirts and speaking in her heavy local dialect rather than formal Japanese.
Ms Tanaka was even disciplined for her remarks about former Prime Minister Keizo Obuchi after his death last year.
"Obuchi proudly said he's the king of debt - that's why he's a dead duck and he deserves to be," she said.
She is the daughter of former 1970s Prime Minister and Liberal Democratic Party (LDP) kingmaker Kakuei Tanaka, and has clashed with powerful figures in the ruling party on many occasions.
Ms Tanaka believed that her ageing father was betrayed by a breakaway faction during a 1985 LDP feud.
The faction, called Keiseikai, is headed by former Prime Minister Ryutaro Hashimoto. Ironically, the new LDP president, Junichiro Koizumi, defeated Mr Hashimoto, a Keiseikai member, in Tuesday's party election.
Difficult times
Whilst it was her father who normalised Japan-China relations in 1972, Ms Tanaka takes over the foreign affairs portfolio at a time of strained diplomatic and trade ties between Japan and its Asian neighbours, particularly China.
But she has little top-level experience, having only headed the Science and Technology Agency in 1994-1995.
She was elected to the government in 1993 from a Niigata Prefecture constituency.
Popular
Mr Koizumi will hope that Tanaka's personable style will help enhance the party's image.
The LDP has been tainted by numerous corruption scandals in recent years, and it was the latest of these that forced Yoshiro Mori to step down as prime minister.
Mr Mori proved a gaffe-prone leader who upset the public with comments that recalled Japan's wartime militarism, and for his decision to continue playing golf after he was told that a US submarine had collided with a fishing vessel, killing nine Japanese.