Park Jung-hyun, a former editor at Kodansha who worked on popular manga like Attack on Titan and The Seven Deadly Sins, was convicted of murdering his wife in 2019.
The Tokyo High Court upheld the conviction, rejecting Park's claims of suicide and finding inconsistencies in his story.
The court considered evidence suggesting strangulation and found Park's explanations about the events leading to his wife's death unconvincing.
Park has been sentenced to 11 years in prison, and his plans to appeal the decision are likely to keep him tied up in the legal system for some time.
