[2] Bacik was able to overcome low poll numbers nationally for the Labour Party[3] as well as defy attempts by Fine Gael and Sinn Féin to define the by-election as an ideological showdown solely between the two of them.

[16] After the February 2020 Irish general election, prolonged negotiations led to the formation in June 2020 of a three-party coalition government, to which Murphy was not appointed.

[19] The writ was moved in the Dáil on 16 June 2021,[20] and on the same day the polling order for the by-election[21] was signed by Murphy's successor as Housing Minister, Darragh O'Brien.

Measures included having hand sanitisers at all polling stations, voters being asked to wear a mask and observe social distancing when voting, and each presiding officers' desk having a perspex screen.

At her campaign launch on 25 June, she called for an end to the tax advantages international property investors receive, stating it is pricing families out of the market.

[71] He stated "I want to speak for a generation stuck in a rent trap or living in their parents' homes", and said he "is not a fan of co-living", a contrast to the Fine Gael incumbent Eoghan Murphy.

Creighton had been expelled from the Fine Gael parliamentary party when she voted against the Protection of Life During Pregnancy Bill 2013, which had permitted abortion under certain limited circumstances.

The Irish Daily Mail subsequently complained that Geoghegan was refusing to answer questions on political issues, especially Fine Gael housing policy.

[81] On Wednesday 7 July 2021, the day before voting, Kate O'Connell announced she would be contacting the Garda Siochana after a fake message which she had not endorsed began circulating on WhatsApp.

The message, coming from a user posing under the guise of an official O'Connell group, played off the perceived rivalry between O’Connell and Geoghegan reported upon during Fine Gael's candidate selection.

It asked O'Connell's supporters to give their votes to Ivana Bacik, Claire Byrne, Deirdre Conroy, Sarah Durcan and Lynn Boylan rather than Fine Gael's candidate James Geoghegan.

The party held to this tactic even after The Irish Times published a poll showing that Ivana Bacik was emerging as the main contender, with Fine Gael sending out a tweet on election day warning their supporters that unless they voted, Sinn Féin would win.

[84][5] Byrne campaigned on providing more housing with improved standards, improving waste and recycling provisions, providing "multipurpose venues" to create and revitalise a "sustainable night-time economy", as well as being a female representative in a constituency without any female Teachtaí Dála, saying "I really believe only women can represent women effectively".

And never is this more evident than in relation to housing", as well as improving healthcare and childcare, tackling climate change, and achieving "a true republic in which church and state are separated".

Bacik described herself as having "more bills passed into law than any other Senator, on issues such as workers' conditions, women's health rights, and LGBT equality".

[93] During the campaign, Boylan received criticism from Fine Gael's by-election candidate James Geoghegan for her stance on the Special Criminal Court.

Durcan was a lead organiser of the #wakingthefeminists campaign which to achieve gender equality in Irish theatre,[95] and describes herself as an "activist arts worker".

Durcan opined that the government had "put corporations and profits over communities, and shoddy short-term fixes over long-term benefits" and suggested that everyone should be able to access affordable housing and expect reasonable waiting times for healthcare services.

[100] Purcell held 'open air' public meetings in the constituency with Gino Kenny in relation to cannabis legalisation[101] and with Paul Murphy in support of rent controls.

During the campaign the National Party's GoFundMe was removed for violating its terms of service; it also emerged that Barrett was under criminal investigation by the Garda Síochána for breaching COVID-19 regulations, as well as road traffic offences.

"[104] On 4 July a debate about the by-election was held on The Week in Politics on RTÉ One, featuring seven candidates from the parties who had placed highest in the 2020 general election.

The five highest polling parties from 2020 had their candidates featured in another debate the next day on 5 July on Today with Claire Byrne on RTÉ Radio 1.

[106] On Sunday 3 July, RTÉ aired an episode of "National Treasures" which contained a segment exploring the family background of Labour's candidate Ivana Bacik.

[113] Around 15:00 IST, Lynn Boylan and Mary Lou McDonald on behalf of Sinn Féin conceded, noting that it was "Ivana's day".

However, blame was also levelled against Fianna Fáil's director of elections Jim O'Callaghan, himself considered a rival and potential ouster of Martin.

[7] O'Callaghan called the result "disappointing" and publicly questioned if Martin was suitable to lead Fianna Fáil into the next general election.

[118][119] The same day Fianna Fáil TD Cathal Crowe told RTÉ Radio 1 that, in his view, Micheál Martin should not lead the party into the next general election.

[119] Similar discontent was felt in Fine Gael, with questions raised internally and externally of the wisdom of Leo Varadkar in endorsing James Geoghegan as the candidate instead of the potentially more popular Kate O'Connell.

Varadkar publicly reaffirmed his support of Geoghegan and dismissed the notion that the defeat, which left the party with no TDs in an area considered its "heartland", was a negative reflection of his leadership.

[111] Sinn Féin leader Mary Lou McDonald praised the effort of their candidate Lynn Boylan while stating her belief that the result of the by-election demonstrated to her the time was right to call a general election.