Hugh was the third son of Count Theobald III of Blois and Countess Adele of Valois, bearing the title count of Bar-sur-Aube. His older brother Count Odo died in 1093, leaving him master of Troyes, where he centred his court, Bar-sur-Aube and Vitry-le-François. In this way the three contiguous countships that formed the core of an emerging Champagne were united in his person, and though he preferred "Count of Troyes", the oldest of his lordships and site of the only bishopric in his domains, many contemporary documents call him the count of Champagne, the title preferred by his descendants.

His first recorded act, a monastic gift in 1094, became the oldest document of the comital archive. The act of his that resonated longest in history was his grant of lands in 1115 to the monk Bernard of the reformed Benedictines at Cîteaux-the Cistercians-in order to found Clairvaux Abbey, a Cistercian monastery at Clairvaux (in the present Ville-sous-la-Ferté), in a wild valley of a tributary of the Aube, where Bernard was appointed abbot and became famous as Bernard of Clairvaux. Hugh's charter makes over to the new foundation Clairvaux and its dependencies, fields, meadows, vineyards, woods and water. A deeply affectionate letter from Bernard to Hugh survives, written in 1125, as Hugh went off for a third time to fight in the Holy Land, joining the Knights Templar, leaving his pregnant wife, and disinheriting his son Odo - according to later sources, Hugh believed himself impotent and never acknowledged his son. Instead, he transferred his titles to his nephew, who became Theobald II of Champagne. Odo's two sons, Odo II of Champlitte and William of Champlitte were important figures in the Fourth Crusade.