Caswell represented North Carolina in the Continental Congresses of 1774 and 1775. When the militia district of New Bern was formed on May 4, 1776; Caswell was appointed to command that minuteman region. As such, he led the Provincial Congress' force at the Battle of Moore's Creek Bridge (1776). Soon thereafter, the Provincial Congress disbanded minuteman battalions in favor of militia. In 1780, he was commissioned major general of militia and state troops. At the Battle of Camden Court House in 1780, his troops fled after Virginia militia broke and ran in panic, exposing him to attack without greater defense, leaving the Continentals behind to suffer defeat.