Rossa founded the Phoenix National and Literary Society and dedicated his life to working towards the establishment of an independent Irish Republic.

After being exiled to the United States in 1870 as part of the Cuba Five amnesty, Rossa worked with other Irish revolutionary organisations there to oppose British rule in Ireland.

His funeral served as a rallying point for Irish republicans and is often cited as a direct stepping stone towards the events of the Easter Rising in 1916.

[6] Rossa became a shopkeeper in Skibbereen, where, in 1856, he established the Phoenix National and Literary Society, the aim of which was "the liberation of Ireland by force of arms",[7] This organisation would later become a front for the Irish Republican Brotherhood (IRB), founded two years later in Dublin.

As part of the raid, Rossa was arrested and held at Richmond Bridewell prison to await trial by the Special Commission on charges of treason felony.

[12] In an 1869 by-election, he was returned to the British House of Commons for the Tipperary constituency, in which he defeated the Liberal Catholic Denis Caulfield Heron by 1054 to 898 votes.

[8] After giving an understanding that he would not return to Ireland, in effect his exile, Rossa was released as part of the Fenian Amnesty of 1870.

Rossa additionally established his own newspaper dedicated to the cause of Irish independence from British rule, The United Irishman.

[12] His paper was used to raise a so-called "resources for civilisation fund," presumably for the purchase of dynamite and other armaments for the Irish struggle.

Historians have argued that her motivation for the assassination attempt was anger at Rossa's role in the "skirmishing fund" which served as a fundraise for the dynamite campaign.

[8] The new republican movement in Ireland was quick to realise the propaganda value of the old Fenian's death, and Tom Clarke cabled to John Devoy the message: "Send his body home at once".

Against Rossa's wishes to be buried with his father and other victims of the Great Famine,[8] his body was returned to Ireland for burial and a hero's welcome.

[17] The graveside oration, given by Patrick Pearse, remains one of the most famous speeches of the Irish independence movement stirring his audience to a call to arms.

On 6 June 1853, he married Honora "Nora" Eager of Skibbereen, who had four sons (Denis, John, Cornelius Crom and Jeremiah).

[21] Following Rossa's death, political rival Timothy Daniel Sullivan commentated that "No more determined or consistent enemy to British rule ever breathed the air of Ireland",[8] while Patrick Pearse praised Rossa as "the most typical" of Fenian leaders who derived "courage and endurance from the Gaelic tradition".

In James Joyce's "Araby," written between 1905 and 1907, the narrator is walking across Dublin, when he hears "the nasal chanting of street-singers, who sang a come-all-you about O'Donovan Rossa".