In 1955, Shigeru Yoshida's Liberal Party and Kishi's Democratic Party merged as an anti-leftist coalition and was reestablished as the LDP. Abe attended Seikei Elementary School, Seikei Junior High School and Seikei Senior High School. He studied public administration and graduated with a bachelor's degree in political science from Seikei University in 1977. He later moved to the United States and studied public policy at the University of Southern California's School of Public Policy for three semesters. In April 1979, Abe began working for Kobe Steel. He left the company in 1982 and pursued a number of government positions including executive assistant to the Minister for Foreign Affairs, private secretary to the chairperson of the LDP General Council, and private secretary to the LDP secretary-general.

Shinzō Abe was born in Tokyo, to a politically prominent family. His family is originally from Yamaguchi Prefecture, and Abe's registered residence ("honseki chi") is Nagato, Yamaguchi, where his grandfather was born. His grandfather, Kan Abe, and father, Shintaro Abe, were both politicians. Abe's mother, Yoko Kishi, is the daughter of Nobusuke Kishi, prime minister of Japan from 1957 to 1960. Kishi had been a member of the Tōjō Cabinet during the Second World War. Since GHQ's policy changed and became more anti-communist, Kishi was released from Sugamo Prison, and later established the Japan Democratic Party. In his book Utsukushii Kuni e (Toward a Beautiful Country), Abe wrote, "Some people used to point to my grandfather as a 'Class-A war Criminal suspect', and I felt strong repulsion. Because of that experience, I may have become emotionally attached to 'conservatism', on the contrary."

Abe's father Shintaro Abe served in the House of Representatives from 1958 to 1991 and was foreign minister from 1982 to 1986; he is the son of Kan Abe, who served in the House from 1937 to 1946. Abe's mother, Yoko Abe, is the daughter of Nobusuke Kishi, a former prime minister who was at one time imprisoned as a "Class A" war crimes suspect following the war. His older brother, Hironobu Abe, became President and CEO of Mitsubishi Shōji Packaging Corporation, while his younger brother, Nobuo Kishi, became Senior Vice-Minister for Foreign Affairs.

Abe is a member of the Mori Faction (formally, the Seiwa Seisaku Kenkyū-kai) of the Liberal Democratic Party. This faction is headed by former prime minister Yoshirō Mori. Jun'ichirō Koizumi was a member of the Mori Faction prior to leaving it, as is the custom when accepting a high party post. From 1986 to 1991, Abe's father, Shintaro, headed the same faction. The Seiwa Seisaku Kenkyū-kai has 60 members in the House of Representatives and 26 in the House of Councillors.

Abe married Akie Matsuzaki, a socialite and former radio disc jockey, in 1987. She is the daughter of the President of Morinaga, a chocolate manufacturer. She is popularly known as the "domestic opposition party" due to her outspoken views, which often contradict her husband's. Following her husband's first stint as prime minister, she opened an organic izakaya in the Kanda district of Tokyo, but is not active in management due to the urging of her mother-in-law. The couple have no children, having undergone unsuccessful fertility treatments earlier in their marriage.

Shinzō Abe was elected to the first district of Yamaguchi Prefecture in 1993 after his father's death in 1991, winning the most votes of the four Representatives elected in the SNTV multi-member district. In 1999, he became Director of the Social Affairs Division, Deputy Chief Cabinet Secretary in the Yoshirō Mori and Junichirō Koizumi Cabinets from 2000–2003, after which he was appointed Secretary General of the Liberal Democratic Party.

Since 1997, as the bureau chief of "Institute of Junior Assembly Members Who Think About The Outlook of Japan and History Education", Abe supported the controversial Japanese Society for History Textbook Reform and the New History Textbook.

In 2000, Abe's home and the office of his supporters in Shimonoseki, in Yamaguchi Prefecture, were attacked with molotov cocktails on numerous occasions. The perpetrators were several yakuza members belonging to the Kudo-kai, a Kitakyushu-based designated boryokudan syndicate. The reason for the attacks was believed to be that Abe's local aide refused to give cash to a Shimonoseki real estate broker in return for supporting a Shimonoseki mayoral candidate in 1999.

The Asahi Shimbun also accused Abe and Shōichi Nakagawa of censoring a 2001 NHK program concerning "The Women's International War Crimes Tribunal". The "tribunal" was a private committee to adjudicate comfort women; about 5,000 people including 64 victims from Japan and abroad attended. The committee members, who claimed to be specialists of international law, claimed that Emperor Hirohito and the Japanese government were responsible for the use of comfort women. The TV program, however, did not mention the full name of the tribunal and keywords such as "Japanese troops" or "sexual slavery", and it also cut the sight of the tribunal, the host grouping, statements of the organizer, and the judgement itself. Instead, it presented criticism against the tribunal by a right-wing academic and his statement that "there was no abduction of sex slaves and they were prostitutes".

In 2002 negotiations between Japan and North Korea, Prime Minister Koizumi and General Secretary Kim Jong-il agreed to give abductees permission to visit Japan. A few weeks into the visit, the Japanese government decided that the abductees would be restricted from returning to North Korea where their families live. Abe took credit for this policy decision in his best-selling book, Towards a Beautiful Nation (美しい国へ, Utsukushii kuni e). North Korea criticized this Japanese decision as a breach of a diplomatic promise, and the negotiations aborted.

Abe's first cabinet was announced on 26 September 2006. The only minister retained in his position from the previous Koizumi cabinet was Foreign Minister Taro Aso, who had been one of Abe's competitors for the LDP presidency. In addition to the cabinet positions existing under Koizumi, Abe created five new "advisor" positions. He reshuffled his cabinet on 27 August 2007.

A 2007 Washington Post editorial, "Shinzo Abe's Double Talk" also criticized him: "he's passionate about Japanese victims of North Korea—and blind to Japan's own war crimes". In The New York Times in 2014, and editorial called Abe a "nationalist" who is a profound threat to American–Japanese relations, and an opinion piece labeled Abe's position on the subject of comfort women a "war on truth". The same editorial presented him as a revisionist, a view largely accepted by the international and part of the Japanese press.

The Second Abe cabinet revived the Council on Economic and Fiscal Policy (CEFP) that had played a key role in formulating economic policy during the Koizumi cabinet, but had been abandoned by the 2009–12 DPJ administrations.

Abe was chief negotiator for the Japanese government on behalf of the families of Japanese abductees taken to North Korea. As a part of the effort, he accompanied Koizumi to meet Kim Jong‑il in 2002. He gained national popularity when he demanded that Japanese abductees visiting Japan remain, in defiance of North Korea.

Abe has visited Yasukuni Shrine on several occasions. While serving as Chief Cabinet Secretary in the government of Junichiro Koizumi, he visited in April 2006, prompting South Korea to describe the trip as "regrettable". He visited again on 15 August 2012, the anniversary of the end of World War II, and after winning the presidency of the Liberal Democratic Party, he visited on 17 October 2012 in an official capacity as party President.

On 28 April 2013, a new public event, the Restoration of Sovereignty Day, was held in Tokyo to mark the 61st anniversary of the end of the US occupation of Japan. It had been proposed by Abe in 2012. The event, which was attended by Emperor Akihito, was denounced by many Okinawans who saw it as celebrating a betrayal, and there were demonstrations in both Okinawa and Tokyo.

In his April speech to Congress, Abe announced that his government would "enact all necessary bills by this coming summer" to expand the Self-Defense Forces' capacity for operations and to give effect to the cabinet's July 2014 decision to re-interpret the constitution in favour of collective self-defense. Therefore, the Abe cabinet introduced 11 bills making up the "Peace and Security Preservation Legislation" into the Diet in May 2015, which pushed for a limited expansion of military powers to fight in foreign conflict. The principal aims of the bills were to allow Japan's Self-Defense Forces to come to the aid of allied nations under attack (even if Japan itself was not), to expand their scope to support international peacekeeping operations, and to allow for Japan to take on a greater share of security responsibilities as part of the US-Japan Alliance.

In 2015, Abe's government refused to admit refugees affected by conflicts in the Middle East and Africa. Abe stated that Japan must solve its own problems before accepting any immigrants. Abe has favored short-term working visas for migrant workers to "work and raise incomes for a limited period of time, and then return home".

At the 2016 election to the House of Councillors, the first that allowed Japanese citizens 18 and over to vote, Abe led the LDP–Komeito pact to victory, with the coalition being the largest in the House of Councillors, since it was set at 242 seats. The election's results opened the debate on constitutional reform, particularly in amending Article 9 of Japan's pacifist constitution, with pro-revisionist parties gaining the two-thirds majority being necessary for reform, alongside a two-thirds majority in the House of Representatives, which would ultimately lead to a nationwide referendum. Abe remained relatively quiet on the issue for the remainder of the year, but in May 2017, announced that the constitutional reform would be in effect by 2020.

The 2017 general election was held on 22 October. Prime Minister Abe called the snap election on 25 September, while the North Korea crisis was prominent in the news media. Political opponents of Abe say the snap election was designed to evade questioning in parliament over alleged scandals. Abe was expected to retain a majority of seats in the Diet. Abe's ruling coalition took almost a majority of the vote and two thirds of the seats. The last minute campaigning and voting took place as Typhoon Lan, the biggest Typhoon of 2017, was wreaking havoc on Japan.

In March 2018, it was revealed that the Finance ministry (with Finance minister Tarō Asō at its head) had falsified documents presented to the parliament in relation to the Moritomo Gakuen scandal, to remove 14 passages implicating Abe. It was suggested that the scandal could cost Abe his seat as Liberal Democratic party's leader. Further accusations arose the same year that Abe had given preferential treatment to his friend Kotarō Kake open a veterinary department at his school Kake Gakuen. Abe denied the charges, but support for his administration fell below 30% in the polls, the lowest since taking power in 2012. Those who called for him to step down included former prime minister Jun'ichirō Koizumi.

At a press conference after his official re-election as LDP President, Abe announced that the next stage of his administration would focus on what he called "Abenomics 2.0", the aim of which was to tackle issues of low fertility and an aging population and create a society "in which each and every one of Japan’s 100 million citizens can take on active roles". This new policy consisted of targets which Abe referred to as "three new arrows"; to boost Japan's GDP to 600 trillion yen by 2021, to raise the national fertility rate from an average of 1.4 to 1.8 children per woman and stabilise the population at 100 million, and to create a situation where people would not have to leave employment in order to care for elderly relatives by the mid 2020s. Abe explained that the government would take measures to increase wages, boost consumption, and expand childcare, social security and care services for the elderly to meet these goals.