Starfleet Commander In Chief
From FEInfobase
The Starfleet Commander In Chief is the highest position in Starfleet. Whomever holds the position will normally hold the rank of Fleet Admiral and are the Supreme Commander of all Starfleet Forces. They can only receive orders from the Federation President and Federation Council.
Kathryn Janeway and Jean-Luc Picard both held this title before their deaths. The current Starfleet Commander In Chief is Fleet Admiral Daniel Taylor.