Hatoyama was born to a samurai family of the Katsuyama clan in present-day Minato, Tokyo.

In 1890, at Okuma's urging, he was appointed president of the Tokyo Semmon Gakko, which later became Waseda University.

[1] His wife, Haruko Hatoyama, was a co-founder of what is known today as Kyoritsu Women's University.

His son is former Prime Minister Ichirō Hatoyama, who founded and was the first president of the Liberal Democratic Party (LDP).

Yukio became Prime Minister on September 16, 2009, following a win by the opposition coalition in the 2009 elections.