Capgrave was born in Bishop's Lynn, now King's Lynn, Norfolk – "My cuntre is Northfolke, of the town of Lynne" (Life of St Katharine, 16). His parents are unknown but he may have been the nephew of a namesake who obtained a doctorate of theology at Oxford in 1390 and was also an Augustinian friar. Capgrave the younger joined the order at Lynn in about 1410 and was ordained in 1416 or 1417. He then studied theology at the order's school in London. By 1421, he was already a lector, qualified to teach at all but one of the order's levels of schooling. He was then sent by the prior-general to do further studies in Cambridge, where he delivered his examinatory sermon in Latin in 1422. He later wrote an English version of this as his treatise on the twelve orders that follow the rule of St Augustine. His progress from ordination to the degree of master of theology is said to have been the fastest on record.
Capgrave's earliest work was a Life of St Norbert in English some time before 1422. There followed a succession of exegesis, many of them now lost. His lost commentaries, entitled In regum, are known to have been dedicated to Humphrey of Lancaster, 1st Duke of Gloucester and to John Low, prior-provincial of the Augustinians in 1427–33 and later a bishop. Capgrave was present when the foundation stone of King's College, Cambridge was laid on 2 April 1441 by Henry VI. Several hagiographies and royal biographies followed, including one in English of St Katharine. By 1446 he was prior of the Augustinian friary at Bishop's Lynn.
Capgrave paid a visit to Rome in 1449–50 for the holy year of Jubilee and left an account that provides a glimpse into the histories, legends, traditions and publicly held attitudes in the church at that time. Some later works were dedicated to William Grey, king's proctor in Rome in 1450 and later bishop of Ely.
Only twelve of Capgrave's 45 known works survive, including the seven in English. Perhaps the most important for posterity was his Abbreviacion of Cronicles, which provides a framework for world history within an Augustinian framework, drawing on the St Albans chronicles by Thomas Walsingham and others. According to the Encyclopedia of Medieval Literature, the book "brings together what Capgrave felt were the most important events in world and later British history. He often moralized historical incidents, and consistently revealed a bias for Christians and later Englishmen in his depiction of events."
Capgrave died on 12 August 1464 at Bishop's Lynn.
- ODNB entry: Retrieved 29 June 2011. Subscription required.
- F. X. Roth: The English Austin friars, 1249–1538 ( New York: Augustinian Historical Institute, 1961-6) I, 174. Cited in ODNB entry.
- C. A. Mills (ed.): Ye Solace of Pilgrimes. A Description of Rome, circa AD 1450, by John Capgrave, an Austin Friar of King's Lynn (London etc.: Oxford University Press, 1911). Retrieved 29 June 2011.
- Encyclopedia of Medieval Literature. Ed. Robert Thomas Lambdin and Laura Cooner Lambdin (London: Fitzroy Dearborn, 2000). Retrieved 30 June 2011.
- "John Capgrave". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
- Cousin, John William (1910). " Capgrave, John". A Short Biographical Dictionary of English Literature. London: J. M. Dent & Sons. Wikisource
- Chisholm, Hugh, ed. (1911). "Capgrave, John". Encyclopædia Britannica (11th ed.). Cambridge University Press.