Mary Lou McDonald

After school, McDonald attended Trinity College Dublin, from which she received a bachelor's degree in English Literature. She later studied industrial relations at Dublin City University, and also received a Master of Arts degree in European Integration Studies from the University of Limerick in 1995. Her career to date has seen her involved in diverse roles, including consultant for the Irish Productivity Centre, researcher for the Institute of European Affairs, (a think-tank run by then Labour TD Brendan Halligan) and trainer in the Partnership Unit of the Educational and Training Services Trust.

McDonald became involved with the Irish National Congress, a cross-party republican organisation, and became chairperson in 2000, leading a protest in Dublin against the involvement of the city's Lord Mayor in the unveiling of a plaque at the location where the Grand Orange Lodge of Ireland held its first meeting in 1798.

In September 2003, McDonald attracted criticism when she spoke at a rally in Dublin to commemorate Seán Russell, an IRA leader with links to Nazi Germany.

In 2004, McDonald became Sinn Féin's first MEP in Ireland, when she was elected at the 2004 European Parliament election for the Dublin constituency, receiving over 60,000 first preference votes. She served as one of two Sinn Féin MEPs, the other being Bairbre de Brún who was representing Northern Ireland. In 2007, she was shortlisted for the 'MEP of the Year' award by the European Parliament magazine watching for "making the most valuable contribution in the field of employment policy". During her time in office she led the Sinn Féin campaign against the Treaty of Lisbon, which was rejected in the Republic in 2008. McDonald sat as a member of the European Parliament's Employment and Social Affairs Committee, and as a substitute of the Civil Liberties Committee.

For the 2009 European Parliament election, the number of seats for Dublin in the European Parliament was reduced from four to three. McDonald was in a tight race for the last seat against Fianna Fáil's Eoin Ryan and the Socialist Party leader Joe Higgins. McDonald lost her seat to Higgins, being eliminated at the fifth count. Her first preference vote had declined to nearly 48,000.

In June 2009, McDonald faced criticism after it emerged her campaign office was selling IRA souvenirs and memorabilia.

In 2012, McDonald was awarded 'Opposition Politician of the Year' by TV3's Tonight with Vincent Browne political talk show.

In November 2014, McDonald refused to leave the Dáil chamber despite a vote suspending her, after she had questioned Tánaiste Joan Burton on if the government would allow payments to be taken from citizen's wages or social welfare payments if they did not comply with the payment of newly introduced water charges. McDonald argued Burton failed to directly answer her questions and was being deliberately evasive and intractable. Her decision not to leave the chamber was in protest of Burton's refusal to answer her questions. She, along with a number of Sinn Féin colleagues, remained in the chamber for four and a half hours. In response the Ceann Comhairle Seán Barrett adjourned the Dáil for a number of days.

In December 2015, McDonald initially backed Thomas "Slab" Murphy, who she described as a "good republican" despite him having been convicted on nine charges of tax evasion, following a trial held in the Special Criminal Court after the last person to testify against Murphy in a court was bludgeoned to death after a 1999 court case in Dublin. She later failed to back party leader Gerry Adams' assertion that Thomas Murphy is a "good republican" after a BBC Spotlight investigation accused Murphy of being a "mass murderer".

After her re-election to the Dáil in 2016 general election, in which she topped the poll in Dublin Central, she became Sinn Féin's All-Ireland Spokesperson for Mental Health and Suicide Prevention, which she held until being elected president of Sinn Féin in 2018.

At a Sinn Féin party conference on 18 November 2017, Gerry Adams was re-elected party leader, but announced that he would ask the Sinn Féin party leadership to call for a special Ard Fheis to be held within three months to choose a new president, and that he would not stand for re-election as TD for the Louth constituency in the next election.

At the close of nominations to succeed Adams on 20 January 2018, McDonald was announced as the President-elect of Sinn Féin, as she was the sole nominee to enter the race. She was confirmed as president at a special Ard Fheis on 10 February 2018 in Dublin.

In March 2019, McDonald was criticised by some, including Fine Gael politician Simon Coveney, for walking behind a banner in the New York City St. Patrick's day parade which read "England Get Out of Ireland". The banner itself had been a part of the parade since 1948, however, the appropriateness of its message was questioned in a post-Good Friday Agreement era. In the immediate aftermath of the incident support for Sinn Féin in opinion polls dropped from 18% to 13%, with McDonald apologising for her actions shortly afterwards, but stated she believed the message to be directed at the British state, not the English people.

Shortly afterwards on 24 May 2019, the 2019 European Parliament election in Ireland and 2019 Irish local elections were held simultaneously. In the European elections, Sinn Féin lost 2 MEPs and dropped their vote share by 7.8%, while in the local elections the party lost 78 (almost half) of their local councillors and dropped their vote share by 5.7%. The result was considered "disastrous" for Sinn Féin. McDonald stated "It was a really bad day out for us. But sometimes that happens in politics, and it’s a test for you. I mean it’s a test for me personally, obviously, as the leader".

On 26 June 2020, Fianna Fáil, Fine Gael, and the Green Party formed a coalition government, leaving Sinn Féin as the largest opposition party, and McDonald as Leader of the Opposition. She dismissed the coalition agreement as a "marriage of convenience", and accused Fianna Fáil and Fine Gael of conspiring to exclude Sinn Féin from government.

In April 2020, she announced that she had tested positive for COVID-19 following a test she took on 28 March. In a statement she said that she had recovered from the condition but had developed pleurisy in her right lung. She said that the Public Health Doctor had told her that she was no longer infected or infectious.