Naoto Kan was voted in as prime minister by the Diet on Friday, shortly after the ruling Democratic Party of Japan elected him as its new president.
The change of leadership comes only two days after Kan's predecessor, Yukio Hatoyama, abruptly announced his resignation over his failure to resolve a dispute over the relocation of U.S. Marine Corps Air Station Futenma in Okinawa, and money scandals that have dogged his tenure.
Kan, 63, who has become the 94th prime minister, will take over an administration reeling from dwindling public support little over a month before an Upper House poll.