
An election to Dublin City Council took place on 5 June 2009 as part of that year's Irish local elections. 52 councillors were elected from thirteen electoral divisions by PR-STV voting for a five-year term of office.

Bank of Ireland Mortgage Bank v Coleman [2009] IESC 38; [2009] 2 ILRM 363; [2009] 3 IR 699 is an Irish Supreme Court case in which the Court clarified the inherent jurisdiction of the court with respect of a solicitor's misconduct. The court also considered the remedies available where a solicitor is in breach of a solicitor's undertaking.

The post-2008 Irish banking crisis was the situation whereby, due to the Great Recession, a number of Irish financial institutions faced almost imminent collapse due to insolvency. In response, the Irish government instigated a €64 billion bank bailout. This then led to a number of unexpected revelations about the business affairs of some banks and business people. Ultimately, added onto the deepening recession in the country, the banks bailout was the primary reason for the Irish government requiring IMF assistance and a total restructuring of the Irish Government occurred as result of this.

The Peter Bergmann case is an unsolved mystery pertaining to the death of an unidentified man in County Sligo, Ireland. From 12 to 16 June 2009, a man using the alias "Peter Bergmann" visited the seaport town of Sligo in northwest Ireland. He used this alias to check into the Sligo City Hotel, where he stayed during the majority of his visit, and was described by the hotel staff and tenants as having a heavy German accent. The man's movements were captured on CCTV throughout the town; however, the details of his actions and intentions remain unknown. His interactions with other people were limited, and little is known of his origins or the reason for his visit to Sligo.

A by-election was held in the Dáil Éireann Dublin Central constituency in Ireland on Friday, 5 June 2009, following the death of the Independent Teachta Dála (TD) Tony Gregory on 2 January 2009. The by-election was held on the same day as the 2009 European and local elections. A by-election was held in the Dublin South constituency on the same date. There was no legal requirement on when to hold a by-election in Ireland in 2009 but they were generally held within six months.

A by-election was held in the Dáil Éireann Dublin South constituency in Ireland on Friday, 5 June 2009, following the death of the Fianna Fáil Teachta Dála (TD) Séamus Brennan on 9 July 2008. As Brennan was a Fianna Fáil TD, that party had the responsibility of deciding when the by-election should take place. It was held on the same day as the 2009 European and local elections. There was no legal requirement on when to hold a by-election in Ireland in 2009 but it was generally held within six months. A by-election in the Dublin Central constituency was held on the same date.

The post-2008 Irish economic downturn in the Republic of Ireland, coincided with a series of banking scandals, followed the 1990s and 2000s Celtic Tiger period of rapid real economic growth fuelled by foreign direct investment, a subsequent property bubble which rendered the real economy uncompetitive, and an expansion in bank lending in the early 2000s. An initial slowdown in economic growth amid the international financial crisis of 2007–08 greatly intensified in late 2008 and the country fell into recession for the first time since the 1980s. Emigration, as did unemployment, escalated to levels not seen since that decade.

Minister for Justice, Equality and Law Reform v Dolny [2009] IESC 48, was an Irish Supreme Court case. The court found that a European extradition can be applied if the offense is very similar to an offense in Irish statute.

Operation Seabight, or Sea Bight, is the codename used to describe the tracking and eventual seizure of up to €750 million of cocaine off the Irish coast in November 2008, originally thought to have been the largest such haul in the history of Ireland and one of the largest in Europe in 2008. The figures were later revised to show that this was in fact the second largest haul in Irish history. The seizure took place off the south-west coast and eclipsed the discovery of €440 million of cocaine near Mizen Head in July 2007. A 60-foot (18 m) yacht containing more than seventy bales of the substance was seized by a team of European anti-drugs agencies led by Irish authorities. Three men were also apprehended and later each was sentenced to ten years in jail.

The Twenty-eighth Amendment of the Constitution Act 2009 is an amendment of the Constitution of Ireland which permitted the state to ratify the Treaty of Lisbon of the European Union. It was approved by referendum on 2 October 2009.