Fitzgerald, Sir John (d. a.7 May 1712), 2nd baronet, soldier, and patron of the poet Ó Bruadair, was born, probably by 1640, the eldest of at least five sons of Sir Edmund Fitzgerald (d. c.1666), 1st baronet, of Clonlish, Co. Limerick, and his wife, Mary Fitzgerald. His father belonged to a junior branch of Desmond Fitzgeralds, while his mother's maiden name is unknown. At the time his father died Fitzgerald had been in Nantes for two years, perhaps for his education. Dáibhí Ó Bruadair (qv), who eulogised Sir Edmund on his death, transferred his allegiance to the son, now the 2nd baronet, and the relationship, despite an apparent estrangement at one point, was enduring. Sir Edmund had suffered great losses in the royalist cause, and restoration came after his death, in 1670, when his son recovered 3,000 acres of family land.
Sir John was accused of involvement in the ‘popish plot’ in 1681, and was summoned to London. Ó Bruadair prophesied in verse that the king, once he saw Fitzgerald, would realise that he was incapable of treason. A grand jury at Westminster threw out the charge, but Fitzgerald endured a miserable imprisonment in London.
His military career began in the reign of James II (qv), whose lord lieutenant, Clarendon (qv), in 1686 contrasted the discretion of Sir John with the alarm caused by those catholic army officers who spoke of recovering their lands. He was lieutenant-colonel in the infantry regiment of Mountcashel (qv), and colonel of his own foot regiment in 1689, which was at the siege of Derry, where his brother Captain Maurice Fitzgerald was killed. He sat for Co. Limerick in the commons in the Irish parliament summoned in 1689 by James II.
After the war, his estates and baronetcy forfeited by attainder, he embarked for France in November 1691, disappointed that more of his followers did not accompany him. He commanded the Limerick regiment and fought in Flanders, where he distinguished himself at the battle of Landen in 1693. He also fought in the French service in Italy in 1696 and on the Rhine in 1697. His later years are obscure, but he was certainly dead before 7 May 1712. He married, in 1674, Ellen, probably a daughter of Maurice Fitzgerald of Caisleán an Lisín, Co. Cork. She was living in 1703; it is not known if they had children.
Fitzgerald was the officer commanding the Jacobite troops who occupied TCD in September 1689, and appears to have been responsible for removing the fifteenth-century manuscript known as the Book of Lecan from its library. The book subsequently turned up in Paris in the possession of James Terry (d. 1725), the Jacobite genealogist, who claimed to have purchased it from Fitzgerald, and was later returned to Dublin, to the RIA.