Gervase was of aristocratic stock, claiming kinship with Patrick, Earl of Salisbury, and relations allegedly descended from a fey serpent-woman recognizable as the Melusine, suggesting an alliance with the House of Lusignan in Poitou, with which England had contemporary dynastic connections.

He travelled widely, studied and taught canon law at Bologna, was in Venice in 1177, at the reconciliation of Pope Alexander III and Frederick Barbarossa, and spent some time in the service of Henry of Anjou, and of his son, "Henry the Young King". For the latter he composed a Liber facetiarum (‘Book of entertainment’), now lost, as well as the basis for what would become the Otia imperialia. He also served Henry's uncle William of Champagne, Archbishop of Reims. He spent some time between 1183 and 1189 at the Sicilian court of the Norman William II, who had married Henry's daughter Joan (1177). From William he received the gift of a villa at Nola in Campania.

At some point after William's death in 1189 Gervase settled in Arles and was appointed Marshal of the Kingdom of Arles in 1198 by Otto IV, Holy Roman Emperor and grandson of King Henry. Ex officio he accompanied Otto to Rome in 1209 on the occasion of his coronation. The following year Gervase was enmeshed in the papacy's struggle with his patron Otto, who was excommunicated by Pope Innocent III. Gervase employed the next years, from 1210 to 1214, writing the Otia imperialia ("Recreation for an Emperor") for his patron.

Gervase's Otia imperialia has also been titled Liber de mirabilibus mundi, Solatia imperatoris, and Descriptio totius orbis. It is an encyclopedic miscellany of wonders in the manner of speculum literature, divided into three parts (decisiones) concerning history, geography, and physics. During the following three centuries it was much read, and it was twice translated into French in the fourteenth century. The philosopher Gottfried Leibniz, who edited parts of it, called it a "bagful of foolish old woman's tales"; its modern Oxford University Press editors less dismissively report "a wealth of accounts of folklore and popular belief", but Catholic apologists respect it most of all for the support it offers of Innocent's papal claims in his conflicts between Church and Empire.

He also wrote a Vita abbreviata et miracula beatissimi Antonii ("Shortened life and miracles of the most blessed Antony") and a Liber de transitu beate virginis et gestis discipulorum ("Book of the martyrdoms of the blessed virgins and acts of the disciples").

Details of his latter years are uncertain. It has been suggested that, after the resounding defeat of Otto and his English ally John at the battle of Bouvines (1214), Gervase was forced to retire to the duchy of Braunschweig, where he became, and died, provost of Ebstorf, and it is apparent that his work was known to the authors of the Ebstorf world map (ca 1234—40). However, it is recorded by Ralph of Coggeshall that he became a canon in later life, and other evidence suggests that he may have been a member of the Premonstratensians of l'Huveaune.

The arguments for Gervase of Tilbury being the maker of the Ebstorf map are based on the name Gervase, which was an uncommon name in Northern Germany at the time and on some similarities between the world view of the mapmaker and Gervase of Tilbury. The editors of the Oxford Medieval Texts edition of Gervase of Tilbury's Otia Imperialia conclude that although them being the same man is an "attractive possibility", to accept it requires "too many improbable assumptions".