Goofy is the captain of the royal guard in Disney Castle. In Kingdom Hearts, he serves King Mickey as a knight and travels with Sora and Donald while searching for their missing king.
Goofy's role deliberately contrasts with his gentle, comic personality. Although he is a trained royal guard captain, he is a pacifist who prefers defending himself and his friends with a large shield rather than attacking with a blade. His shield also becomes his distinctive weapon in the party's battles.
Donald Duck holds the neighboring court position of royal magician, while Mickey is the king they serve. That division of roles causes a common mix-up: Donald and Goofy are both royal retainers, but only Goofy is the captain of Disney Castle's guard. Across later Kingdom Hearts games, his title is sometimes phrased as captain of the royal knights or Disney Castle guards, referring to the same character and office.