John David FitzGerald, Baron FitzGerald, PC, PC (Ire) (1 May 1816 – 16 October 1889)^[1] was an Irish judge and Liberal politician.

Born in Dublin, he was the son of the merchant David FitzGerald and his wife Catherine, eldest daughter of David Leahy.^[2] His sister Kate was married to Charles Robert Barry and his youngest sister Emily to Denis Caulfield Heron.^[3] FitzGerald was educated privately and was called to the bar by King's Inns in 1838.^[2] In 1870, he received an Honorary Doctorate of Laws by the University of Dublin.^[4]

FitzGerald became a Queen's Counsel in 1847, and was a judge of the Munster circuit.^[2] He entered the House of Commons in 1852, sitting for Ennis the next eight years.^[5] In 1855, FitzGerald was first elected a bencher, then nominated Solicitor-General for Ireland.^[4] He became Attorney-General for Ireland a year later, on which appointment he was sworn of the Privy Council of Ireland.^[2] FitzGerald held the former post until 1858 and after a break for a year, again until 1860, when he was appointed Judge on the Court of Queen's Bench (Ireland).^[4] On 23 June 1882, he was created a Lord of Appeal in Ordinary with the life peerage title of Baron FitzGerald, of Kilmarnock, in the County of Dublin.^[6] Six days later, he was additionally sworn of the Privy Council of the United Kingdom.^[4]

In 1846, he married Rose, second daughter of John Donohoe, and had by her three sons.^[7] She died in 1850, and FitzGerald remarried Hon. Jane Matilda Mary, daughter of Lieutenant-Colonel Arthur Francis Southwell and Mary Ann Agnes Dillon, and sister of Thomas Southwell, 4th Viscount Southwell.^[7] By his second wife, he had four sons and six daughters.^[7] The former Conservative politician Amber Rudd is his great-great-granddaughter.