Jinz was the seventh generation of his family to serve in Starfleet. He enrolled in Starfleet Academy to appease his father, a high-ranking member of Starfleet Command. He performed without distinction, earned adequate specialist ratings, and did no less than he was asked, intending to retire after serving a minimum tour of duty.
In 2268, despite requesting service on a planet or starbase, Jinz was transferred to the Enterprise by special order 13-G-9085, surprising Leonard McCoy and Montgomery Scott, who didn't feel Jinz had met the qualifications to serve on the Enterprise. He boarded from Transport Station 19-B and immediately confessed his circumstances to Kirk.
The next day, Kirk briefed Jinz and included him in a landing party to visit the Sanoora host planet. They both endured unusual medical treatment to survive deadly exposure to a radiation similar to sigma rays. After beaming down, Dahvi gave them a tour, including flying over the Great Canyon in an aircar.
When a faction of the Sanoora government seized control of the Sanoora Supreme Council, they withheld further treatment. Jinz and Kirk rapidly developed symptoms, their skin fading to expose skeletons. Jinz panicked and begged to join the rebels. He offered to prove himself by shooting Kirk, and Bir handed him a pistol. But after Spock announced a way to permanently counteract the radiation planet-wide, Jinz relented, apologizing to Kirk for his cowardice. Bir grabbed the pistol and aimed at Kirk. Jinz dove between them and was shot to death.