Since there is no purser on most ships in the United States Merchant Marine, the steward is the senior person in the department, whence its name.

The chief steward directs, instructs, and assigns personnel performing such functions as preparing and serving meals, ensuring that they are both delicious and nutritious.

The chief steward also plans menus, compiles supply, overtime, and cost control records.

In the United States Merchant Marine, in order to be occupied as a chief steward a person has to have a Merchant Mariner's Document issued by the United States Coast Guard.

Chief stewards on large passenger vessels can be considered to be officers.