Fitzgerald was a Roman Catholic nobleman who led two unsuccessful uprisings against English rule in the province of Munster. He was a member of the 16th century ruling Geraldine dynasty who rebelled against the crown of Queen Elizabeth I in response to the onset of the Tudor conquest of Ireland. He led the first of the Desmond Rebellions in 1569, spent a period in exile in continental Europe, but returned with an invasion force in 1579. He died shortly after landing. His rebellions were strongly associated with counter-reformation Catholic ideology.

In 1568, following the arrest and imprisonment of his cousin Gerald Fitzgerald, 14th earl of Desmond, on charges of resisting the authority of England's Queen Elizabeth I, Fitzmaurice was proclaimed leader of the Fitzgeralds of Munster. Allying with his family's traditional rivals, the Butlers, he initiated an uprising against the English in 1569, but by 1573 he had given up the struggle and accepted a pardon.

In 1575 Fitzmaurice travelled to the Continent to seek support for the Irish Roman Catholic cause. Philip II of Spain and Pope Gregory XIII both encouraged his plan for a Catholic invasion of Ireland, but offered almost no material aid. Fitzmaurice landed at Dingle on 18 July 1579, with a small force of Italians and Spaniards, accompanied by the papal legate Nicholas Sanders. Within a month, however, he was betrayed—at the instigation of the English—by several of his followers and killed in a skirmish. The rebellion was not completely quelled until 1583.

FitzMaurice was one of the first Irish leaders to use the Catholic cause as an explicit justification for rebellion against the crown.

Plaque: James Fitzmaurice Fitzgerald leader of the Geraldine Revolt arrived in Dingle Harbour on the 13th July 1579, with military aid from Spain and Rome, during the Elizabethan Wars