 He fought at the Battle of Prestonpans, but deserted to the Highland Jacobites.He subsequently fought for the Jacobites, but after they were defeated at the Battle of Culloden, he fled to France, accompanying his commander and clan captain, Colonel Charles Stewart of Ardshiel (Ardshiel was not the chief of the Appin Stewarts, but took command in the absence of the chief).After joining one of the Scottish regiments serving in the French Army, Stewart was sent back to Scotland to collect rents for the exiled clan leaders and to recruit soldiers for the French crown.