George Townshend was the son of Charles Townshend, 3rd Viscount Townshend and Audrey Ethelreda (Harrison) Townshend. After his education at Eton College and St. John's College, Cambridge, he joined the army. He participated in the War of the Austrian Succession, the Battle of Culloden against Bonnie Prince Charlie Stuart in Scotland, and in the Seven Years' War. He reached the rank of major general during this period.

After succeeding his father to the viscount title in 1764, Townshend was named Lord Lieutenant of Ireland in 1767. He worked with Prime Minister Lord North to increase British control over Ireland until he was replaced in 1772.

Townshend returned to the office of Master-General of the Ordnance under the North ministry in 1772. By 1782 he was promoted to the rank of full general, and he was created Marquess Townshend in 1787. Attaining the rank of field marshal in 1796, Townshend died in 1807.

In 1751 Townshend married Charlotte Compton, 15th Baroness Ferrers of Chartley, with whom he had 8 children. After her death in 1770, he married Anne Montgomery in 1773, who served as Mistress of the Robes to Caronline, Princess of Wales from 1795-1820. They had 6 children.