Dr. Sakezō Sado serves aboard the space battleship Yamato as its medic. Originally a veterinarian, he transitioned to ship's surgeon after Earth's war with Garmillas. Sado provides frequent comic relief through his deep fondness for sake, often seen clinging to tables during warp transitions while his sake bottle stays firmly secured. Despite this carefree attitude, he displays serious dedication to medical duties and crew health, persistently urging Captain Okita to undergo surgery for his worsening condition.

He shares a close bond with his yellow tabby cat, Mi-kun, who accompanies him everywhere. Mi-kun exhibits unique behaviors like sitting upright and performing a "Yamato salute" on command, and even shares Sado's taste for sake.

Three years post the Yamato's return from Iscandar, Sado attends a crew reunion at Earth's "Hero's Hill" honoring the late Captain Okita, leading the tribute amidst Earth's rebuilt defenses and the newly launched Andromeda. He later joins the crew's decision to mutiny and reclaim the Yamato after Earth Defense Command ignores warnings about the White Comet Empire and orders the ship decommissioned. During the boarding, Sado vouches for Hajime Saito and his elite Space Cavalry unit, securing their inclusion despite initial hesitation from acting commander Susumu Kodai.

As the Yamato battles the White Comet Empire, Sado continues his medical duties through intense combat. He is among the crew killed when the Yamato suffers catastrophic damage during the final assault on the enemy's mobile fortress, Gatlantis.