He was born at 174 James Street, Dublin, to Thomas Cosgrave, grocer, and Bridget Nixon.[2] He trained for a medical career at the Catholic University of Ireland though did not complete his studies, instead working as a pharmacist.
In 1914 he joined the Irish Volunteers and took part in the 1916 Easter Rising, at the Marrowbone Lane Distillery; he was captured, court-martialed, and sentenced to death, but this was later commuted to five years’ penal servitude.[3]
Cosgrave's death, from nephritis,[5] only eight weeks after winning his seat in the 4th Dáil triggered a by-election for his seat. It was held on 12 March 1924 and won by the Cumann na nGaedheal candidate, James O'Mara. Cosgrave was an officer in the Irish army on his death.
