He held the titles of Count of Rochefort-en-Yvelines and Châtelain of Châteaufort and of Gometz, and was Seneschal of France under Philip I the Amorous, 1104-1106.
Guy joined with the Lombard contingent in the minor Crusade of 1101, later joining the army of Stephen of Blois.
[1] He apparently rebelled against Louis VI, King of France (once his son-in-law), when he was killed.
Guy first married Elisabeth from an unknown family.
He then married Adelais de Crécy, widow of Bouchard II, Count of Corbeil, grandson of Mauger, Count of Corbeil.