Mayor of Osaka City
His Osaka Metropolis plan faced fierce opposition from other politicians, including then Osaka City Mayor Kunio Hiramatsu. Hashimoto resigned as governor of Osaka on 31 October 2011, before finishing his first term, in order to run for Osaka city mayor. In November he was elected as mayor, alongside Ichirō Matsui of One Osaka who succeeded him as governor.
During the election campaign, weekly magazines Shukan Shincho, Shukan Bunshun and Shincho45, published articles which refer to his father's criminal record and burakumin origin. Hashimoto criticized the articles on Twitter.
After the election, Hashimoto founded the Ishin Seiji Juku, a cram school for training future political leaders, which admitted 2,000 students in its first class in March 2012.
In 2012 a poll of civil servants working in Ōsaka city was conducted, requiring disclosure of those with tattoos on their body. The survey found 110 employees out of 33,500 had at least one tattoo. Hashimoto commented that civil servants have no right to have tattoos and suggested that those who do should resign. Inciting further controversy, 2 July 2012 Hashimoto made the comment to newly appointed ward mayors of Ōsaka that civil servants cannot expect to have personal privacy or fundamental human rights while working for the public.
In September 2012, he launched Nippon Ishin No Kai, or the Japan Restoration Association, a national extension of the Osaka Ishin no Kai. It was the first national political party that was based in Osaka rather than Tokyo, and achieved party status by winning the support of seven sitting diet members.
The Osaka Ishin no Kai suffered several setbacks in 2013, with its candidate losing the Sakai mayoral election in September, and the party losing its majority in the prefectural assembly in December 2013 after four members defected over the sale of the government's stake in Osaka Prefectural Urban Development, the operator of the Semboku Rapid Railway.
In the wake of controversial comments about comfort women (see below) and after failing to gain consensus for his plan to merge Osaka City and Osaka Prefecture, Hashimoto announced his resignation as mayor in February 2014, and said he would stand for re-election to seek a new mandate from voters.
Osaka voted down the Osaka Metropolis plan by a thin margin in a May 2015 referendum. Following the defeat of his core policy proposal, which had been supported by the national government, Hashimoto announced that he would retire from politics upon expiration of his term as mayor which he formally left later in December of the following year. In June, he was invited to Tokyo for a meeting with Prime Minister Shinzo Abe, who voiced his support for the defeated plan and also sought Hashimoto's input on upcoming national security legislation.
Hashimoto's political agenda planned the privatization of the municipal transport sector (subways, bus services and peripheral bus lines), waterworks, hospitals, and trash collection. It included the reduction of the city staffing from 21,600 units in 2012 to 19,350 by 2015. The electoral program of the Ishin no Kai proposed to cut funding to classical orchestras, the bunraku (the national puppet theatre) and to the Osaka Human Rights Museum, and legalizing gambling as a new way to generate revenue.
In 2008, Hashimoto reduced the wages of public school teachers as well as the public contribution directed to the private schools. In 2013, he forced the majority of the Osaka's schools to make scholastic ability test rankings public in order to promote the role of the private sector, the competition between schools and school operators and the use of quantitative methods of evaluation. This approach applied a political control on the education, two areas that had been traditionally kept separated after the Second World War.