His paternal grandfather, Ichirō Hatoyama, was a major politician; he served as Prime Minister and was a founder and the first President of the Liberal Democratic Party in 1956.

As Prime Minister, he restored diplomatic relations with the Soviet Union, which cleared the way for Japan's membership in the United Nations.

His younger sister-in-law Emily Hatoyama (鳩山エミリ) who is Kunio's wife, an Australian Japanese, was a TV personality in Japan.

[8] Because of his quirky hairstyle, prominent eyes, and eccentric manner, he is known by his supporters and his opposition alike as "ET" or "The Alien",[9] a nickname his wife states he earned because of how different he is from old-style Japanese politicians.

The DPJ promised to end lavish spending on public works projects associated with LDP and to divert that money to tax cuts and subsidies for households.

[12] Hatoyama's popularity soon began to falter after the DPJ struggled to meet the high expectations they set in the midst of a sliding economy.

Although Yukio Hatayoma was prime minister for less than a year, he had a wide range of achievements to his name by the time that he left office.

[19] However, according to NHK in 2010 prosecutors chose not to pursue him citing insufficient evidence of criminal activity, although a secretary was given a suspended prison sentence, and a review panel commented: "it is difficult to believe Hatoyama's assertion he was unaware of the falsifications.

The United States government hoped that Hatoyama would honor a 2006 agreement to relocate the base to a less populated part of Okinawa and move 8,000 marines to Guam.

[26] Hatoyama worked to deepen economic integration with the East Asian region, pushing for a free trade zone in Asia by 2020 and proposing Haneda airport as a 24-hour hub for international flights.

The first few months saw an exchange of visits, including one by favored successor to China's leadership Xi Jinping, for whom Hatoyama hastily arranged an appointment with Emperor Akihito.

[29] On 7 January, the Daily Yomiuri reported high-level discussion over a further exchange of visits between the two countries to promote reconciliation over historical issues.

"Beijing aims to ease anti-Japan sentiment among the Chinese public by having Hatoyama visit Nanjing and express a sense of regret about the Sino-Japanese War", the paper reported.

He cited breaking a campaign promise to close an American military base on the island of Okinawa as the main reason for the move.

He also mentioned money scandals involving a top party leader, Ichirō Ozawa, who resigned as well, in his decision to step down.

[32] Hatoyama had been pressed to leave by members of his party after doing poorly in polls in anticipation of an upper house election in July 2010.

When Prime Minister Yoshihiko Noda introduced legislation to raise the consumption tax from 5% to 10% Hatoyama was one of 57 DPJ lower house lawmakers who voted against the bill.

[40] In the lead-up to the 16 December 2012 general election the DPJ announced that it would not endorse candidates who did not agree to follow its current policies, including the consumption tax hike and support for joining the negotiations to enter the Trans-Pacific Partnership.

"[44] In August 2015, Hatoyama visited the Seodaemun Prison History Hall, where he knelt and bowed before a memorial to Korean independence activists killed by Japan during 1905-1945.

[45] Hatoyama practices the Transcendental Meditation technique and delivered the Maharishi University of Management commencement address on 23 May 2015 and was awarded an honorary degree of Doctor of Laws.

It said Hatoyama had "helped change his country from a de facto one-party state into a functional democracy", through the DPJ victory in the 2009 general election.