This division is lead by the command staff and contains the enlisted division of Administrative Command. All departments ultimately report to this division. It is led by the Commanding Officer. In addition key functions normally termed "Operations", such as communications and navigation, fall under this division. Tactical, which handles weapons control and defensive systems operation, also works nominally within this department to operate communications equipment. Essentially, the Executive officer functions as the "Chief of Operations", and coordinates the cross-department functions of bridge and ship operations.

This division is tasked with the maintenance and operation of the vessel's systems. As a unit, they contain the enlisted division of Technical Engineering and Operations Support, and they work closely with the Air Group. The unit is led by the Chief of Engineering.

This division's task is obvious—the care and welfare of the crew. In practice, the medical division works closely with all departments, but particularly with science when dealing with threats to the ship, or new problems that may arise in a given mission. There is no dedicated enlisted division that coincides with Medical, however the grade of Medtech and Hospital Corpsmen within the Administrative Command division function under the de facto leadership of the Chief Medical Officer. Within the department there are various subsections, such as Chief Surgeon, or Chief Counselor, however, all of these sub-department heads report directly to the CMO.

Protecting the vessel from all threats is the most important, but not only, role the Security division plays aboard a starship. They function as not only a military police, but also serve as the ships first line of defense and work closely with the Marine division during ground operations.

Possibly the most diverse group aboard any starship, the Science department serves a vital roll in the Federation's primary mission of exploration. Officer's in this department work closely with the Command division to help solve problems the ship encounters, as well as conducts research of its own, often in concert with civilian scientists stationed aboard the ship. Science is headed by the Chief Science Officer who usually also holds the title of "Director of Scientific Research", though not by default.

Aboard some ships and stations, such as the Excalibur, there is a dedicated "air" group. In those situations, all secondary craft and their operations fall under the direct supervision of the Squadron commander, nominally titled 'Chief of the Air Group' or CAG.

With the expansion of the Starfleet Marine Corps, a number of new roles aboard Federation starships in regards to this division have been created. Typically, the bulk of the Marine Deployment aboard a starship will be enlisted crew, while Marine officers serve in any branch of starships' operational needs. Marines may be called upon to fulfill any number of mission requirements and must be among the most flexible departments aboard a starship or station. The Marine detachment aboard a starship is under the direction of the highest ranking officer who rank, depending on the size of the deployment, is typically a Colonel or Major and under the supervision of the Commanding Officer of the vessel.