In 2267, Harold was the sole survivor of a Gorn massacre that destroyed the colony. He was later discovered by the crew of the USS Enterprise, before they were ambushed by the Gorn, and he was thereafter treated in the starship's sickbay. (TOS: "Arena")
Harold was played by actor Tom Troupe.
The final draft script of "Arena" describes Harold as a lieutenant, a rank which Kirk too – in both the script and the actual episode – identifies him as. Although Kirk addresses him as "lieutenant" only once in the episode, however, the script includes three occasions on which the captain does so and another time on which Dr. McCoy does likewise. These references are despite the fact that no rank braids were present on Harold's uniform. His clothing was a rare black-collared variant of the beige operations division uniform style, also seen on Commander Hansen in TOS: "Balance of Terror". Harold's name was given in the credits and final draft script only. The script additionally refers to him as a communications officer, describing the rubble amid which he is discovered as the remains of his communications equipment.