Little is known of his life, however it is clear that Alan entered the schools no earlier than the late 1140s; first attending the school at Paris, and then at Chartres. He probably studied under masters such as Peter Abelard, Gilbert of Poitiers, and Thierry of Chartres. This is known through the writings of John of Salisbury, who is thought to have been a near exact contemporary student of Alan of Lille. His earliest writings were probably written in the 1150s, and probably in Paris. Alan spent many years teaching at the school in Paris and he attended the Lateran Council in 1179. Though the only accounts of his lectures seem to show a sort of eccentric style and approach, he was said to have been good friends with many other masters at the school in Paris, and taught there, as well as some time in southern France, into his old age. He afterwards inhabited Montpellier (he is sometimes called Alanus de Montepessulano), lived for a time outside the walls of any cloister, and finally retired to Cîteaux, where he died in 1202.
He had a very widespread reputation during his lifetime and his knowledge, more varied than profound, caused him to be called Doctor Universalis. Many of Alan’s writings are unable to be exactly dated, and the circumstances and details surrounding his writing are often unknown as well. However, it does seem clear that his first notable work, Summa Quoniam Homines, was completed somewhere between 1155 and 1165, with the most conclusive date being 1160, and was probably developed through his lectures at the school in Paris. Among his very numerous works two poems entitle him to a distinguished place in the Latin literature of the Middle Ages; one of these, the De planctu naturae, is an ingenious satire on the vices of humanity. He created the allegory of grammatical "conjugation" which was to have its successors throughout the Middle Ages. The Anticlaudianus, a treatise on morals as allegory, the form of which recalls the pamphlet of Claudian against Rufinus, is agreeably versified and relatively pure in its latinity.