The Chief of Starfleet Security is a Starfleet flag officer who oversees Starfleet Security. In 2367, Vice Admiral Thomas Henry held this post, followed by Admiral Raner in 2370. (TNG: "The Drumhead", "The Pegasus")

It is not stated whether this is Raner, or another flag officer who replaced her following the events of "The Pegasus".

In 2371, Benjamin Sisko took the decision to relieve Odo of his duties regarding security for Starfleet operations- Michael Eddington having been appointed head of Starfleet security matters on the station while Odo remained responsible for the station's Bajoran Militia detachment and civilian population- to the Chief of Starfleet Security herself, but was unable to have it overturned. (DS9: "The Search, Part I")

In 2372, Benjamin Sisko's knowledge of the Founders led to his brief promotion to Chief of Starfleet Security on Earth. (DS9: "Homefront")