Yuriko Koike, chosen by Tokyo voters as their first-ever female governor, has vowed to initiate sweeping reforms of the metropolitan government and address the shortage of day care facilities.
The 64-year-old former defense minister was a Lower House lawmaker with the ruling Liberal Democratic Party until Sunday's election.
She ran without the backing of the ruling party's Tokyo chapter, beating out its chosen candidate, former Iwate Gov. Hiroya Masuda.
An expert on the Middle East and a graduate of the University of Cairo, Koike worked as an Arabic interpreter and a news broadcaster before entering politics.
She was first elected to the Upper House in 1992 with the now-defunct Japan New Party. She won a seat in the Lower House the following year and, after associating with several other political parties, joined the LDP in 2002.
Koike spearheaded the Cool Biz initiative in 2005 as environment minister in Prime Minister Junichiro Koizumi's government, encouraging Japan's suit-bound office workers to dress more casually in summer and lessen the use of air conditioning.
During the gubernatorial campaign, Koike pledged to increase transparency and "put the metropolitan government back into the hands of Tokyo's people."
She promised to loosen regulations on day care facilities for children to eliminate waiting lists, and to improve the capital's disaster resilience.
As for the 2020 Tokyo Olympics, Koike has said the cost of hosting the event has to be appropriate and acceptable to residents amid growing concern about the ballooning price tag.