Kiichirō Hatoyama

Hatoyama was born on 26 July 1976 in California, when his father Yukio Hatoyama, later prime minister, was studying for his PhD in operations research at Stanford University.^[3] Hatoyama is a member of the Hatoyama family, and his other notable relations include former his great grandfather Ichirō Hatoyama, prime minister of Japan and the founder of the Liberal Democratic Party, Ichirō's father Kazuo Hatoyama, prominent jusrist and politician in Meiji era Japan, and Ichirō's son Iichirō Hatoyama.

Hatoyama was educated at the Gakushuin Junior High School and Senior High School at Komaba, University of Tsukuba. Following family tradition, he matriculated at the University of Tokyo (UTokyo) in 1995, where he chose to specialise in urban engineering after the Shingaku Furiwake. During his time at UTokyo, he was a cellist in the university orchestra.^[2] He completed his master’s degree at UTokyo in 2001 and went on to earn a PhD in transport engineering in 2007. His thesis was entitled Guideline Formulation for Signalized Intersection Design Considering Impacts on Pedestrians' Psychology.^[4]

He remained at his alma mater as assistant professor and lecturer until 2017, when he was appointed associated professor at Nagaoka University of Technology. Beginning in 2008, he spent three years at Moscow State University as a visiting professor.^[5]

He is a member of the Democratic Party for the People, having joined in 2023.^[6] He was first elected in the 2024 Japanese general election for the Tokyo proportional representation block. He lost his Tokyo 2nd district contest to the incumbent, but was elected via the PR block after getting enough votes (73.4% sekihairitsu) to obtain his party's last block seat.^[1]

He was defeated in the 2026 election.