Admiral McKenna was a Starfleet officer during the 2260s.
In 2268, McKenna assigned the USS Enterprise to transport Ambassador Zarv and his specialists to the Ammdon system. When Captain Kirk protested, noting that the ship and crew required some much-needed maintenance work and shore leave, McKenna replied that the Enterprise was the only nearby ship in good enough condition, and that there was no time to waste.
She had him look at dry docks bays one and four, one unnamed starship without its engines, and one USS Scarborough without its bridge and she gave four unmanned ensigns commendations after taking command when Captain Virzi and his officers were blasted into atoms by the Romulans. (TOS novel: Mutiny on the Enterprise)