He studied at the University of Paris and lectured there on theology till 1206, when Pope Innocent III, with whom he had formed a friendship at Paris, called him to Rome and made him cardinal-priest of St. Chrysogonus. His piety and learning had already won him prebends at Paris and York and he was recognized as the foremost English churchman.
On the death of Hubert Walter, archbishop of Canterbury (1205); some of the younger monks elected to the see Reginald, the subprior, while another faction under pressure from King John chose John de Grey, bishop of Norwich. Both elections were quashed on appeal to Rome and sixteen monks of Christ Church, who had gone to Rome empowered to act for the whole chapter, were ordered to proceed to a new election in presence of the pope. Langton was chosen and was consecrated by the pope at Viterbo June 17, 1207.
There followed a struggle between John and Innocent III which brought great misery upon unhappy England. The king proclaimed that any one who recognized Stephen as archbishop should be treated as a public enemy, and expelled the Canterbury monks (July 15, 1207), who were now unanimous in support of Stephen. In March, 1208, Innocent placed England under the interdict and at the close of 1212, after repeated negotiations had failed, he passed sentence of deposition against John, committing the execution of the sentence to Philip II of France in January, 1213.
In May John yielded and in July Stephen (who since his consecration had lived at Pontigny in France) and his fellow exiles returned to England. His first episcopal act was to absolve the king, who swore that unjust laws should be repealed and the liberties granted by Henry I should be observed-- an oath which he almost immediately violated.
Stephen now became a leader in the struggle against John and none of the barons did more than he to rescue England from John's tyranny. At a council of churchmen at Westminster, August 25, 1213, to which certain lay barons were invited, he read the text of the charter of Henry I. and suggested a demand for its renewal. In the sequel, largely through Stephen's efforts, John was forced to grant the Magna Carta (June 15, 1215).
Since John now held his kingdom as a fief of the Holy See the pope espoused his cause and excommunicated the barons. For refusing to publish the excommunication Stephen was suspended from all ecclesiastical functions by the papal commissioners and on November 4 this sentence was confirmed by the pope, although Stephen appealed to him in person. He was released from suspension the following spring on condition that he keep out of England till peace was restored and he remained abroad till May 1218. Meanwhile both Innocent and John died and all parties in England rallied to the support of Henry III.
Stephen continued his work unremittingly and effectively for the political and ecclesiastical independence of England. In 1223 he again appeared as the leader and spokesman of the barons, who demanded of Henry the confirmation of the charter. He went to France to demand for Henry from Louis VIII of France the restoration of Normandy, and later he supported the king against rebellious barons. He obtained a promise from Pope Honorius III, that during his lifetime no resident legate should be again sent to England, and won other concessions from the same pontiff favorable to the English Church and exalting his see of Canterbury.
Of great importance in the ecclesiastical history of England was a council which Stephen opened at Osney April 17, 1222; its decrees, known as the Constitutions of Stephen Langton, are the earliest provincial canons which are still recognized as binding in English church courts.
Stephen was a voluminous writer. Glosses, commentaries, expositions, and treatises by him on almost all the books of the Old Testament, and many sermons, are preserved in manuscript at Lambeth Palace, at Oxford and Cambridge, and in France.
The only one of his works which has been printed, besides a few letters (in The Historical Works of Gervase of Canterbury, ed. W. Stubbs, ii. London, 1880, Rolls Series, no. 71, appendix to preface) is a Tractatus de translatione Beati Thomae (in J. A. Giles's Thomas of Canterbury, Oxford, 1845), which is probably an expansion of a sermon he preached in 1220, on occasion of the translation of the relics of St. Thomas (Thomas Becket); the ceremony was the most splendid which had ever been seen in England. He also wrote a life of Richard I, and other historical works and poems are attributed to him.