Fields was a male Human Starfleet enlisted crewmember in the 23rd century. He served aboard the USS Enterprise between 2266 and 2267 under the command of Captain James T. Kirk, during a historic five-year mission which the starship undertook.
In 2266, Fields was assigned to the forward phaser control room as a phaser specialist. When the Enterprise went to condition red upon news of a Romulan Bird-of-Prey attacking Outpost 4, all crewmembers reported to battle stations. Fields, along with Brenner, reported on the readiness of the weapon batteries. He was injured by radiation burns, when the Enterprise destroyed an atomic weapon, and reported to sickbay for treatment. (TOS: "Balance of Terror")
Background information Edit
The duty jumpsuit Fields wore in "Balance of Terror" 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 Brenner). Similarly, although not referenced on screen, Paul Schneider's script for "Balance of Terror" named this character (along with Brenner) as a "phaser specialist".
Following his appearance as Fields in "Balance of Terror", John Arndt's later character appearances were all unnamed. Assuming they were all the same character, Mr. Fields might have been a career generalist (similar to Mr. Kyle and Mr. Leslie) since he appears in a command division yellow jumpsuit in "Balance of Terror", a command yellow officer uniform in "Dagger of the Mind", and a red security uniform in "Miri".