On social issues, he supported successful constitutional referendums to legalise same-sex marriage and to liberalise Ireland's abortion laws.

A member of Fine Gael since his teenage years, he ran unsuccessfully in the 1999 local elections but was co-opted onto Fingal County Council in 2003.

[1] Following Kenny's resignation, Varadkar defeated Simon Coveney in the 2017 Fine Gael leadership election and was appointed Taoiseach on 14 June 2017.

[5] Varadkar served as Tánaiste and Minister for Enterprise, Trade and Employment from June 2020 to December 2022, when he exchanged positions with Fianna Fáil leader Micheál Martin to begin his second term as Taoiseach.

[27] It was also during 2010 that Varadkar was reported to be a supporter of an attempt to oust Enda Kenny as leader of Fine Gael and replace him with Richard Bruton.

[25] When Fine Gael formed a coalition government with the Labour Party, Varadkar was appointed Minister for Transport, Tourism and Sport on 9 March 2011.

[33][34] Taoiseach Enda Kenny repeated the line of the Government of Ireland, that the State would not require a further bailout from the European Union or the International Monetary Fund, and said he had warned all ministers against publicly disparaging the economy.

[50] His government nearly collapsed as a result of the Garda whistleblower scandal and Tánaiste (Deputy Prime Minister) Frances Fitzgerald's role in it.

Fianna Fáil, the main opposition party, who were in a confidence-and-supply agreement with Fine Gael, threatened a motion of no confidence in the government.

After days of gridlock, the crisis was averted, after Fitzgerald resigned from the cabinet to prevent triggering an election that could jeopardise the Irish position in Brexit negotiations.

[52][53] Shortly after the Fitzgerald crisis, an impasse was reached in the Brexit talks, as Arlene Foster, leader of the Democratic Unionist Party, objected to a deal agreed to by Varadkar, British Prime Minister Theresa May, and President of the European Commission Jean-Claude Juncker.

[59] Irish Times columnist Pat Leahy claimed Varadkar had ended 2017 "on a high" and IrishCentral called it the Taoiseach's "finest hour".

[62] In January 2018, he announced that the referendum to repeal Ireland's 8th Amendment which prevented any liberalisation of restrictive abortion laws would take place in May.

[65] On 24 January 2019, Varadkar said in an interview with Euronews that he was standing firm on the Irish backstop and called Brexit an act of self-harm that was not fully thought through.

[69] On 14 January 2020, Varadkar sought a dissolution of the 32nd Dáil, which was granted by President Michael D. Higgins, and scheduled a general election for 8 February.

Varadkar added that Fine Gael was "willing to step back" to allow Sinn Féin, as the winner of the popular vote, to have the first opportunity to form a government.

[74] On 20 February, Varadkar offered his resignation to President Higgins at Áras an Uachtaráin, pursuant to the constitution, remaining, however, as Taoiseach until the formation of a new government.

While in Washington, D.C., ahead of Saint Patrick's Day, Varadkar announced measures intended to stop COVID-19 spreading, including the closure of all schools, universities and childcare facilities from the following day, as well as the closure of all cultural institutions and the cancellation of "all indoor mass gatherings of more than 100 people and outdoor mass gatherings of more than 500 people".

[80][81] It was also plagiarised by Irish businessman Peter Bellew, the chief operating officer at British low-cost airline group EasyJet.

[82] In response to a March 2020 Health Service Executive appeal to healthcare professionals, Varadkar rejoined the medical register and offered to work as a doctor one day each week.

[86] The coalition deal allowed for a government to be formed on 27 June, with Fianna Fáil leader Micheál Martin taking over as Taoiseach.

[5] On 31 October 2020, Village published an article alleging that Varadkar had leaked confidential documents, including a draft contract between the Health Service Executive and general practitioners that was agreed but still subject to acceptance by GPs at the time, and officially unavailable to members of the Oireachtas.

This request was seconded by Sinn Féin's health spokesperson, stating: "The facts for me here are clear – Leo, as the leader of Fine Gael and Taoiseach at the time, passed on a document to a friend about sensitive negotiations involving hundreds of millions of euro of taxpayers' money.

[93][94][95] Varadkar apologised in the Dáil for "errors of judgement" in sharing a copy of the contract, and rejected any suggestion that he had anything to gain personally from giving the IMO document to the NAGP president as "false and deeply offensive".

[118] Varadkar, alongside his party Fine Gael, universally opposed Brexit, and much of his time during his first tenure as Taoiseach was spent in negotiations with the British government over how the shared border between the United Kingdom and Ireland would operate.

[132] In November, he commented on the release of 8-year-old Irish-Israeli citizen Emily Hand, who had been kidnapped by Hamas, saying, "An innocent child who was lost has now been found and returned... A little girl was snatched from her home and held captive for almost seven weeks.

[135] In March 2024, he resisted calls to boycott a planned Saint Patrick's Day (17 March) meeting with the American president Joe Biden, who has been the target of fierce criticism in Ireland over his stance on the Gaza war;[136][137] Varadkar noted "differences of opinions [between the U.S. and Ireland] in relation to Israel and Gaza".

[138] In a 2010 interview, Varadkar stated that while he did not consider homosexuality morally wrong, he opposed same-sex marriage, although he supported civil partnerships.

[139][140] In 2022 Varadkar stated he was in support of the transgender community, and credited a gender recognition legislation brought into law during the Fine Gael/Labour government of 2011 to 2016 as a "huge step forward" in Ireland in terms of trans issues.

[119] In a 2022 interview, Varadkar was critical of British politician Priti Patel in her role as Home Secretary, stating that her plan to "send asylum seekers to Rwanda is disgusting".