Brenner was a male Human Starfleet crewman who lived during the mid-23rd century. He served in the command division aboard the USS Enterprise under Captain James T. Kirk, during a historic five-year mission that starship undertook. In 2267, he was assigned to the forward phaser control room as a phaser specialist.
That same year, when the Enterprise went to condition red upon news of a Romulan Bird-of-Prey attacking Outpost 4, all crewmembers reported to battle stations. Brenner and Fields reported on the readiness of the weapon batteries. He was injured by radiation burns, when the Enterprise destroyed an atomic weapon. He reported to the sickbay for treatment. (TOS: "Balance of Terror")
Background information
Brenner was played by Sean Morgan, who later portrayed Harper and O'Neil.
Brenner was not named on screen; his name originates from the "Balance of Terror" script. His name also appears on an autograph card released by Rittenhouse Archives.
The duty jumpsuit Brenner wore had no indication of rank and was worn by both non-commissioned and commissioned officers. His rank was given, however, in a cast list written for the script of "Balance of Terror", which referred to him as a "crewman" (in common with Fields). The script also specified Brenner (again, along with Fields) as a "phaser specialist."