Kenjirō Ōta serves as an officer in the navigation division of the space battleship Yamato, holding the rank of Ensign with the specific duty of Chief of Weather. He is a native of Osaka, which is reflected in his bright and outgoing personality. Known for his consistently cheerful disposition, Ota acts as a mood-maker among the crew, using his optimism to lighten the atmosphere during the tense and dangerous voyage.

Despite the serious nature of the Yamato's mission to save Earth, Ota maintains a lighthearted presence on the bridge. His role as Chief of Weather involves observing and reporting space weather and the ship's accompanying trajectory information, a technical task he performs as part of the navigation team. Throughout the journey to Iscandar, he works closely with the chief navigator, Daisuke Shima, and the rest of the navigation division to ensure the ship stays its course.

Over the course of his service, Ota demonstrates notable personal development. Following the Yamato's return to Earth and the subsequent conflicts, his character continues to evolve. Years later, by the time of the voyage to Telezart and the war with Gatlantis, Ota has been promoted to the rank of First Lieutenant. He takes on the greater responsibility of leading the navigation division aboard the combat carrier Hyuga, where he personally holds the control stick.

This period marks a significant turning point for him, as he is described as no longer being simply the gluttonous mood maker he was in his youth. His long years of experience supporting Daisuke Shima on the Yamato have prepared him for this command role. His key relationships include his enduring professional bond with Shima and his camaraderie with fellow officers such as Yoshikazu Aihara, who serves as the chief communications officer. His abilities lie primarily in stellar navigation and ship handling, honed through years of service on the Yamato's bridge and later applied to leading his own department on the Hyuga.