Both his parents come from wealthy backgrounds, and his father, George Noble Plunkett, has been made a papal count. Despite being born into a life of privilege, young Joe Plunkett does not have an easy childhood.
Plunkett contracts tuberculosis at a young age. This is to be a lifelong burden. His mother is unwilling to believe his health is as bad as it is. He spends part of his youth in the warmer climates of the Mediterranean and North Africa. He spends time in Algiers where he studies Arabic literature and language and composes poetry in Arabic. He is educated at the Catholic University School and by the Jesuits at Belvedere College in Dublin and later at Stonyhurst College, in Lancashire, England, where he acquires some military knowledge from the Officers’ Training Corps. Throughout his life, Plunkett takes an active interest in Irish heritage and the Irish language, and also studies Esperanto. He is one of the founders of the Irish Esperanto League. He joins the Gaelic League and begins studying with Thomas MacDonagh, with whom he forms a lifelong friendship. The two are both poets with an interest in theatre, and both are early members of the Irish Volunteers, joining their provisional committee. Plunkett’s interest in Irish nationalism spreads throughout his family, notably to his younger brothers George and John, as well as his father, who allows his property in Kimmage, south Dublin, to be used as a training camp for young men who wish to escape conscription in Britain during the First World War. Men there are instead trained to fight for Ireland.
Sometime in 1915 Plunkett joins the Irish Republican Brotherhood (IRB) and soon after is sent to Germany to meet with Roger Casement, who is negotiating with the German government on behalf of Ireland. Casement’s role as emissary is self-appointed, and, as he is not a member of the IRB, the organisation’s leadership wishes to have one of their own contact Germany to negotiate German aid for an uprising the following year. Plunkett is seeking, but not limiting himself to, a shipment of arms. Casement, on the other hand, spends most of his energies recruiting Irish prisoners of war in Germany to form a brigade to fight instead for Ireland. Some nationalists in Ireland see this as a fruitless endeavour, and prefer to seek weapons. Plunkett successfully gets a promise of a German arms shipment to coincide with the rising.
Plunkett is one of the original members of the IRB Military Committee that is responsible for planning the Easter Rising, and it is largely his plan that is followed. Shortly before the rising is to begin, Plunkett is hospitalised following a turn for the worse in his health. He has an operation on his neck glands days before Easter and has to struggle out of bed to take part in what is to follow. Still bandaged, he takes his place in the General Post Office with several other of the rising’s leaders, including Patrick Pearse and Tom Clarke, though his health prevents him from being terribly active. His energetic aide-de-camp is Michael Collins.
Following the surrender Plunkett is held in Kilmainham Gaol, and faces a court-martial. Seven hours before his execution by firing squad at the age of 28, he is married in the prison chapel to his sweetheart Grace Gifford, a Protestant convert to Catholicism, whose sister, Muriel, had years before also converted and married his best friend Thomas MacDonagh, who is also executed for his role in the Easter Rising. Plunkett is executed by firing squad on May 4, 1916 and is the fourth and youngest signatory of the Proclamation of the Republic to be executed.
Plunkett’s brothers, George Oliver Plunkett and Jack Plunkett, join him in the Easter Rising and later become important Irish Republican Army (IRA) men. His father’s cousin, Horace Plunkett, is a Protestant and unionist who seeks to reconcile unionists and nationalists. Horace Plunkett’s home is burned down by the Anti-Treaty IRA during the Irish Civil War.