Leo Varadkar is stepping down as Taoiseach in a move that has shocked many political colleagues and the opposition.
The 45-year-old has served in public office for more than 20 years and will stay on as a Dublin West TD.
Mr Varadkar qualified as a medical doctor before moving into politics.
He first became a county councillor when he was co-opted to Fingal County Council in 2003.
He went on to win a seat in the 2004 local elections, after an unsuccessful bid five years earlier.
Leo Varadkar is elected leader of Fine Gael in 2017. Image: Eamonn Farrell/RollingNews.ieIn 2007, he became a TD for Dublin West constituency and was appointed to the Fine Gael front bench.
He became a Government minister in 2011 during Enda Kenny's time as Taoiseach, despite being in opposition to his leadership the year before.
He became the first openly gay serving Cabinet minister in Ireland when he came out in 2015, ahead of the same-sex marriage referendum later that year.
Leo Varadkar holds his hands up before a huge crowd during Pride in Dublin, 24-6-17. Image: Sam Boal/Rollingnews.ieHe served in various ministries before succeeding Enda Kenny as Taoiseach in June 2017, becoming both the first openly-gay person and person of Indian heritage to do so.
He was also the youngest person to hold the office when he became Taoiseach aged 38.
He was also a familiar figure in British politics during negotiations on Brexit.
One of the high points of his time as Taoiseach was the success of the referendum to Repeal the Eighth Amendment in 2018.
Leo Varadkar speaking to the media during the visit of US President Joe Biden to Ireland, 13-4-23. Image: Leah Farrell/RollingNews.ieHe led Fine Gael in the General Election in February 2020, where the party lost 15 seats and was unable to form a government.
He led a caretaker government through the start of the COVID-19 pandemic, before forging a historic three-way coalition Government with Fianna Fáil and the Green Party, which saw Micheál Martin take up role of Taoiseach before Leo Varadkar took over in December 2022.
Most recently Mr Varadkar's Government suffered a double-defeat in the Family and Care referendums at the start of the month.
Leo Varadkar at Aras an Uachtaráin, 16-6-17. Image: Eamonn Farrell/RollingNews.ieAlmost 74% of voters rejected the Care amendment, which proposed removing references to a woman's "life within the home" and mothers' "duties in the home" when providing care, replacing them with an article acknowledging the importance of family members in general, without defining them by gender.
Some 67.7% of voters rejected a second amendment, which had proposed extending the meaning of Family beyond marriage in the Constitution, instead including households based on 'durable relationships'.
He returned from the US and a St Patrick's Day meeting with Joe Biden in Washington DC last week to announce his resignation earlier today.
Additional reporting: Jack Quann
