[1] Simon succeeded his eldest brother Geoffrey V as lord of Joinville, who died without children at Krak des Chevaliers in late 1203 or early 1204 during the Fourth Crusade.

[2] In 1209, he participated in the initial campaign of the Albigensian Crusade, and after the fall of Carcassonne he came back to Joinville.

[a][3] In the war of the Succession of Champagne, he fought for his cousin Erard of Brienne-Ramerupt and his wife Philippa of Champagne against the countess-regent Blanche of Navarre and her son Theobald, because the hereditary office of seneschal was not appointed by Blanche.

Blanche's forces ravaged the lands of Joinville, and she imposed a humiliating surrender agreement: Simon's fortresses were seized, his eldest son Geoffroy was taken hostage, and he was forced to transfer his ancestral castle at Joinville to his brother, Bishop William, as security for his good conduct.

This made John, Geoffrey and Simon half-brother-in-law to Peter II, Count of Savoy This relationship explains the role played by Geoffrey and Simon de Joinville at the English court and their preferment in England.