John Fox Burgoyne was the illegitimate son of Lieutenant General John Burgoyne, soldier, politician and dramatist, best known as the “Gentleman Johnny” whose surrender at Saratoga was one of the decisive episodes in the American War of Independence. Earlier in his life, General Burgoyne had eloped with and married Lady Charlotte Stanley, daughter of the 11th Earl of Derby. They had no children and, after his wife’s death, Burgoyne set up house with a popular singer, Susan Caulfield. His position in society prevented them from marrying, though they had four children together. The eldest of these, John Fox Burgoyne, took his second name from his baptismal sponsor, Charles James Fox, a friend and political ally of his father. After General Burgoyne died in 1792, his children were brought up by his late wife’s nephew, the 12th Earl of Derby. John Fox Burgoyne was educated at Eton and the Royal Military Academy, Woolwich. He was commissioned as a second lieutenant in the Royal Engineers on 28 August 1798 and was later sent to join the British force besieging Valetta, where the French were finally starved into surrender in September 1800. Burgoyne was promoted to lieutenant on 1 July 1800. He continued in the Mediterranean theatre and served as aide-de-camp to General Henry Fox (Charles James Fox’s elder brother) until receiving promotion to second captain on 6 March 1805. Burgoyne took part in the British expedition to Egypt at the end of 1806 and was at the capture of Alexandria in February 1807, the subsequent siege of Rosetta and the withdrawal to Alexandria in April 1807. After returning to Sicily, he joined the staff of Sir John Moore and went with his army to Sweden in May 1808 and Portugal in September 1808. As the engineer officer of the Light Division, he was with the rearguard in the early part of the retreat to Corunna and blew up the bridges at Benavente and Castro Gonzala (29 December 1808) as the French approached. Burgoyne returned to Portugal in April 1809, in the army under Sir Arthur Wellesley .
Burgoyne was at the passage of the Douro (Oporto, 12 May 1809) and, when Wellesley decided in October 1809 to fall back and hold Lisbon, joined with his fellow engineers in the construction of the lines of Torres Vedras. He was commended for his demolition of Fort Concepcion (20 July 1810) and for his command of the Portuguese troops serving with the British at El Bodon (25 September 1811), where he was thanked by Wellington in the field and was noticed by the French Marshal Marmont. As engineer officer of the 3rd Division, he served at Busaco (27 September 1810); the second siege of Badajoz (1–10 June 1811) and Ciudad Rodrigo (stormed 19 January 1812). For his services in leading the assault there, he was promoted to major on 6 February 1812. Burgoyne’s next siege was again at Badajoz (17 March–6 April 1812) where he once more led the 3rd Division’s storming parties. He was rewarded with promotion to lieutenant colonel on 27 April 1812. He subsequently served at Salamanca (22 June 1812); the siege of Burgos (16 September–21 October 1812); Vittoria (21 June 1813); the siege of San Sebastian (stormed 31 August 1813); the passage of the Adour (23–26 February 1814) and the siege of Bayonne (27 February–13 April 1814). His next campaign was in the war against the United States, where he was the chief engineer at New Orleans (8 January 1815) and Fort Bowyer (Mobile Bay, 8–12 February 1815). Burgoyne returned to Europe too late for the battle of Waterloo, but served as chief engineer in the Army of Occupation until 1818.
From 1821 until 1826 Burgoyne was at the Royal Engineers Depot, Chatham. He then returned to Portugal in the force of British mercenaries sent to support the constitutional government against Dom Miguel, the absolutist claimant to the Portuguese throne. He was garrison engineer at Portsmouth between 1828 and 1831, with promotion to colonel on 22 July 1830, after which he became chairman of the Board of Public Works in Ireland. He held this post until 1845, during which time he was promoted to major general on 28 June 1838 and was awarded the KCB. Sir John Burgoyne was appointed Inspector General of Fortifications in 1845. He became involved in relief works during the Irish famine of 1846–1847 and sat as a member of various official commissions, including those to decide on the postal system, and the site of Waterloo Bridge. He became a lieutenant general on 11 November 1851.
In 1853 Burgoyne was sent by the British government, at his own suggestion, to inspect the Turkish fortifications on the lower Danube. On the outbreak of the Crimean War in 1854, he joined the British army under Lord Raglan  at Varna as an official adviser. When the Allies invaded the Crimea, Burgoyne played an important part in the selection of Kalamita Bay as the site for the army’s disembarkation. He was also influential in the Allied decision not to attempt a coup de main against Sevastopol but to march round the city and conduct a regular siege from its south side. This resulted in the Allied forces spending the winter of 1854–55 in the field, for which Burgoyne was much blamed. He was recalled by the Cabinet in February 1855, after continual disagreements with his French allies. Burgoyne’s popularity revived at the end of the war and he received various honours, including a baronetcy in 1856. He became a colonel commandant of the Royal Engineers on 22 November 1854, followed by promotion to general on 5 September 1855 and to field marshal on 1 January 1868. Burgoyne was married and had a daughter, who married an officer in the Army, and a son, Hugh, who joined the Royal Navy and was among the first recipients of the Victoria Cross. Captain Hugh Burgoyne was lost, with many of his crew, when the experimental warship HMS Captain was swamped in the Bay of Biscay in September 1870. Burgoyne never recovered from the loss of the son who had been the focus of his love and hopes. He died from the effects of grief on 7 October 1871, at Pembroke Gardens, London, and his baronetcy became extinct. Sir John Fox Burgoyne was the first field marshal to come from the Corps of Royal Engineers.