The little information that we have about Thierry of Chartres's life and career has become less in recent years: even some of the apparently safer assumptions about him have lately been challenged. It is certain that he was born in Brittany, that he was Chancellor of Chartres in the 1140s, that he retired from this position to a monastery at some point in the 1150s, and died after 1156. It is not certain, though likely, that he was the younger brother of Bernard of Chartres, the renowned teacher – some of whose ideas are recorded by John of Salisbury – who was magister at the school of Chartres from before 1117, and later (till 1124) its chancellor. It is also uncertain how far Thierry's teaching activities, in the years before his own chancellorship, can be linked with Chartres itself, rather than with Paris (as is commonly, though on somewhat meagre evidence, affirmed), or with some other centre.

Like Bernard of Chartres, Thierry made an unforgettable impact on more than one generation of scholars. Today both men would be known as ‘charismatic’ teachers. Among Thierry's disciples, Clarembald of Arras calls him ‘the foremost philosopher in the whole of Europe’, John of Salisbury, ‘the most learned of explorers of the liberal arts’.