He was one of ten children born to Lewis Morris (1726–1798), a signer of the Declaration of Independence, and Mary Walton (1727–1794), a member of a well-known merchant family.

His aunt, Helena Magdalena Morris (1762–1840), was married to John Rutherfurd (1760–1840), a United States Senator from New Jersey who served from 1791 to 1798.

[3] On June 7, 1798, he was appointed as Captain in command of Adams, during the Quasi-War with France and made several successful captures of French vessels.

Recalled to the United States, Morris faced a court of inquiry which decided that he had not "discovered due diligence and activity in annoying the enemy".

[6][7][8] Morris had brought his wife and young son on board with him and was accused of taking actions "more reflective of a concerned husband and father than a military commander in the midst of a war.