Alan Kistler was a protection agent for Federation President Nanietta Bacco during at least the early part of her presidency.

During the Borg Invasion of 2381, President Bacco attempted to rally a fleet of local star powers to fight the invading Borg Collective, and held a summit with numerous ambassadors. Kistler and several other protection agents were present as security when Tholian Ambassador Tezrene confronted Bacco, and flanked the enraged political figure when she stormed out. (ST - Destiny novel: Mere Mortals)

When the Borg reached the Sol system, Bacco and select members of her cabinet gathered in the Monet Room where they expected to witness their destruction, protected by Kistler and Wexler. However, thanks to a plan enacted by several Starfleet vessels - the USS Enterprise-E, USS Aventine, and USS Titan - and a race known as the Caeliar, the invasion was halted and the Borg Collective destroyed forever. Due to this, former Borg drone Seven of Nine collapsed in the Monet Room; Kistler called for a doctor, and then saw the doctor and a pair of medical technicians into the room. In the aftermath, President Bacco addressed the Federation with Kant Jorel and Esperanza Piñiero by her side; Wexler and Kistler escorted them to the stage, and then off and back to the President's office. (ST - Destiny novel: Lost Souls)