He was the son of Henry II of Bar and Philippa of Dreux.

[1] He became count of Bar when his father was killed during the Barons' Crusade in 1239, but news of Henry's death did not reach him until 1240.

As Theobald was still a minor, his mother ruled as regent until 17 March 1242.

Theobald's own children included his successor Henry III and the bishop Reginald of Bar.

The next year, in 1246, Theobald married Jeanne de Toucy,[3] daughter of John, lord of Toucy, Saint-Fargeau and Puisaye and his wife Emma de Laval.