After the Irish famine of 1845-52, the family moved to Dublin where Devoy's mother obtained a job at Watkins' brewery.

Devoy joined the French Foreign Legion and served in Algeria for a year before returning to Ireland to become a Fenian organiser in Naas, County Kildare.

Devoy was arrested in February 1866 and interned in Mountjoy Gaol, then tried for treason and sentenced to fifteen years penal servitude.

[1] Under Devoy's leadership, Clan na Gael became the central Irish republican organisation in the United States.

In 1875, Devoy and John Boyle O'Reilly organised the escape of six Fenians from Fremantle Prison in Western Australia aboard the Catalpa.

In 1879, Devoy returned to Ireland to inspect Fenian centres and met Charles Kickham, John O'Leary and Michael Davitt en route in Paris; he convinced Davitt and Charles Stewart Parnell to co-operate in the "New Departure" during the growing Land War.

[1] Devoy's fundraising efforts and work to sway Irish-Americans to support violent nationalism during World War I included attempts to assist the Easter Rising in 1916.

[4] At the declaration of war between Britain and Germany on 14 August 1914, Casement and Devoy arranged a meeting in New York between the Western Hemisphere's top-ranking German diplomat, Count Johann Heinrich von Bernstorff, and a delegation of Clan-na-Gael men.

At the time, Britain held control of the seas; within days of the start of the war it had cut the transatlantic cable.

After meeting the German ambassador in Rome and presenting Devoy's plan, Kenny met in Germany with Count von Bülow.

He then travelled to Dublin where he told Tom Clarke and other members of the Irish Republican Brotherhood of the arrangement, and carried back to Devoy the IRB's wishlist for guns, money, and military leaders.

The IRB men sent to meet the Libau drove off a pier in the dark and were drowned, and the ship was scuttled by its captain and the guns sent to the bottom of the sea.

With the end of the war, Devoy played a key role in the Friends' advocacy for self-determination for Ireland, in line with Wilson's "Fourteen Points", as distinct from recognition by the United States of the sovereignty of the newly declared Irish Republic.

Devoy was scathingly critical of De Valera's visit, saying of him, "This half-breed Jew has done me more harm in the last two years than the English have been able to do during my whole life.

[9] Devoy Barracks in Naas, County Kildare was named for him and housed the Irish Army Apprentice School from 1956 until its closure in 1998.