[3] After Fumio Kishida was appointed prime minister in October 2021, Asō was moved to the role of Vice President of the Liberal Democratic Party.

Through his maternal grandmother, Aso is also a descendant of the Meiji statesman Toshimichi Okubo, considered one of the founders of modern Japan.

By his own account, his anglophile grandfather Shigeru Yoshida, who had come to see him in connection to attending the funeral of General Douglas MacArthur, was displeased with him acquiring a "lousy Californian accent," leading to him being ordered by his family to study in Britain instead.

[18] Asō was one of the final candidates to replace Koizumi as prime minister in 2006, but lost the internal party election to Shinzo Abe by a wide margin.

Both Abe and Asō are conservative on foreign policy issues and have taken confrontational stances towards some East Asian nations, particularly North Korea and, to a lesser extent, the People's Republic of China.

[19] Asō's views on multilateralism are suggested in a 2006 speech, "Arc of Freedom and Prosperity: Japan's Expanding Diplomatic Horizons".

[20] Asō acknowledged that he would most likely lose to Fukuda, but said that he wanted to run so that there would be an open election, saying that otherwise LDP would face criticism for making its choice "through back-room deals".

On 21 September, one day before votes of Diet party members, Asō reportedly told a crowd of supporters outside Tokyo: "The greatest concern right now is the economy."

[27][28][29] Two days later on 24 September, Asō was designated by the Diet as prime minister, and was formally appointed to the office by the Emperor on that night.

[35] Prime Minister Asō flew to Washington to meet with United States President Barack Obama in February 2009.

Accepting responsibility for the worst (and second-only) defeat of a sitting government in modern Japanese history, Asō immediately resigned as LDP president.

Following Shinzo Abe's second resignation as prime minister in August 2020 due to a resurgence of ulcerative colitis, many speculated Aso would launch a leadership bid.

Aso became the Vice President of the Liberal Democratic Party under the new LDP leader and Prime Minister Fumio Kishida.

"[42] Kyodo News reported that he had said on 4 February 2006, "our predecessors did a good thing" regarding compulsory education implemented during Japan's colonization of Taiwan.

[44][7] On 21 December 2005, he said China was "a neighbour with one billion people equipped with nuclear bombs and has expanded its military outlays by double digits for 17 years in a row, and it is unclear as to what this is being used for.

[46][7] Mainichi Daily News reported that on 9 March 2006 he referred to Taiwan as a "law-abiding country", which drew strong protest from Beijing, which considers the island a part of China.

[47] On 23 September 2008, Akahata, the daily newspaper published by Japanese Communist Party, released a compiled list of these and other statements as the front-page article criticizing Asō.

"[49] While speaking at a meeting of the National Council on Social Security Reform, in 2013, Asō referred to patients with serious illness as "tube persons" and remarked that they should be "allowed to die quickly" if they desired it.

"[50][51] In 2014, while campaigning in Sapporo for the general election, Asō said that rising social welfare costs were not solely due to an aging population.

[7] According to The Japan Times, Asō "raised eyebrows" in June 2018 when he stated that the large support towards the LDP among voters under 35 in the 2017 general election was due to that demographic being less inclined than older Japanese to read newspapers, which had been critical of Abe's handling of cronyism scandals.

"[55] When asked to comment on a formal complaint submitted to his ministry on the alleged sexual harassment, Asō remarked that his "only thought was that it would have been easier to read if they used a bigger font.

Additionally he made the statement that people often associate global warming and the warmer temperature it brings with it as a negative but that there can be "something good" that can come out of it.

[57] In January 2024, Aso referred to foreign minister Yoko Kamikawa as an "obasan" (roughly translated as old lady) and "not particularly beautiful" while remarking on her tenure during a speech in Fukuoka.

[60] In addition, 10,000 Korean conscripts worked in the mine between 1939 and 1945 under severe, brutal conditions in which many of them died or were injured while receiving little pay.

The ministry confirmed that two Australians had died while working at the mine, but declined to release their names or causes of deaths for "privacy reasons".

"[65] Asō's tendency for malapropisms has led comparisons to George W. Bush (see Bushism), and the use of his name, "Tarō" as a schoolyard taunt for unintelligent children.

[67] In 2001, Asō, along with Hiromu Nonaka, was among the LDP's chief candidates to succeed Yoshirō Mori as prime minister of Japan.

During a meeting of LDP leaders at which Nonaka was not present, Asō reportedly told the assembled group, "We are not going to let someone from the buraku become the prime minister, are we?"

[citation needed] In October 2008, the Japanese media reported that Asō dined out or drank in restaurants and bars in luxury hotels almost nightly.

[citation needed] Asō argues that embracing Japanese pop culture can be an important step to cultivating ties with other countries, hoping that manga will act as a bridge to the world.