Mary Lou McDonald has been at the helm of Sinn Féin since 2018 after she succeeded Gerry Adams, who led the party for 34 years.
During her maiden speech as party leader, she said that while she will not fill the shoes of Mr Adams, "the news is that I brought my own".
Born in the middle-class area of Rathgar in May 1969, she is the daughter of Patrick and Joan and has two brothers, Bernard and Patrick and sister, Joanne.
She was educated at the Catholic private fee-paying school Notre Dame des Missions school in Churchtown and went on to study a Bachelors of English Literature at Trinity College Dublin.
She then studied for a Master's degree in European Integration Studies at University College Limerick, as well as studying at Dublin City University (DCU).
Her first links to politics was not with Sinn Féin, but as a researcher and consultant at the Institute of International and European Affairs, a think-tank run by Labour TD Brendan Halligan.
In the late 1990s, she joined the Irish National Congress and Fianna Fáil, before switching to Sinn Féin in 2002 when she ran as a candidate in Dublin West, but failed to get elected after polling 8.02% of first preference votes.
Two years later, she made party history after becoming Sinn Féin's first MEP (below) and again ran as a candidate in the 2007 general election in Dublin Central, but was unsuccessful in winning a seat in the Dáil.
She became vice-president of Sinn Féin in 2009 and in her third attempt at a general election, she won a seat in 2011 in the Dublin Central constituency.
She has been married to Martin Lanigan for 24 years and they have two teenage children, Gearoid and Iseult.
The family home is in Cabra, north Dublin.
After suffering a bruising defeat in the 2018 presidential election and in last year's council and European parliamentary elections, Sinn Féin had braced itself for a tough general election campaign.
After the defeat, some people questioned Ms McDonald's leadership, however she said that her party had "listened and learned" from the election losses and would hope to win more seats in the Dáil.
No one predicted the Sinn Féin surge, least of all those in the party and this is reflected in the decision to field 42 candidates, far short of the 80 seats needed to form a government.
As the opinion polls reported a huge rise in her personal approval rating and in support for Sinn Féin, she fast became one of the main voices of the general election.
She has faced criticism, however, over how she handled the controversy of murdered Co Armagh man Paul Quinn.
It emerged that her colleague and Stormont's Finance Minister Conor Murphy said that Mr Quinn was involved in "criminality" shortly after his murder in 2007.
She told RTÉ's Prime Time debate last week that Mr Murphy withdrew the comments and was going to apologise to the Quinn family.
Ms McDonald, who has used the election to focus on bread-and-butter issues, is undoubtedly preparing herself to be at the centre of the media over the coming days.