He was the son of Reginald I, Count of Bar and lord of Mousson, and Giselle of Vaudémont.
He reestablished wars against his traditional enemies, the Duke of Lorraine and the bishop of Metz.
Reginald was attacked in 1152, escaped to the Abbey of Saint-Mihiel and was excommunicated.
In 1170, Reginald died and was succeeded by his eldest son, Henry, as Count of Bar and Lord of Mousson.
[2] Reginald was married in 1155 to Agnes of Champagne (died 1207),[3] daughter of Theobald II (IV), Count of Blois and Champagne and Matilda of Carinthia, and had the following issue: