Westberg initially started his football career with FC Saint-Cloud located not far from his hometown. He later had a stint at first division club Paris Saint-Germain training at the Camp des Loges before moving on to FC Issy-les-Moulineaux in southwest Paris.
Initially, Westberg played football for FC Saint-Cloud, near his home town. He then trained with Paris Saint-Germain in the top division and later joined FC Issy-les-Moulineaux in southwest Paris.