Yukio Hatoyama (鳩山 友紀夫, born 鳩山 由紀夫, Hatoyama Yukio; born 11 February 1947) is a retired Japanese politician who served as Prime Minister of Japan and Leader of the Democratic Party of Japan from 2009 to 2010. He was the first Prime Minister from the party.
Coming from a prominent Japanese political family, Hatoyama was first elected to the House of Representatives in 1986 to represent the Hokkaido 9th district. He became President of the DPJ, the main opposition party, in May 2009. He then led the party to a landslide victory in the 2009 general election, defeating the long-governing Liberal Democratic Party (LDP), which had been in power for over a decade, becoming prime minister that year.