Born the son of Charles Townshend, 3rd Viscount Townshend, and Audrey Ethelreda Townshend (born Harrison), Townshend was educated at Eton College and St John's College, Cambridge. He joined the army as a volunteer in Summer 1743 and first saw action at the Battle of Dettingen in June 1743 during the War of the Austrian Succession. He became a captain in the 7th Regiment of Dragoons in April 1745 and saw action in the Netherlands. He fought at the Battle of Culloden in April 1746 during the Jacobite Rising, and having been appointed an aide-de-Camp to the Duke of Cumberland and having transferred to the 20th Regiment of Foot in February 1747, he took part in the Battle of Lauffeld in July 1747 during the later stages of the War of the Austrian Succession.