After founding Vivarium, he published some of his most famous games, including Seaman, a virtual pet game which was one of the best selling titles for the Dreamcast in Japan,[1] and Odama, a mix of pinball and real time strategy.

During his tenure there he published the independently developed the game, The Tower, which was licensed under the SimCity series and launched as SimTower abroad.

Yutaka Saitou currently serves as the representative director of both Vivarium and his earlier company OPeNBooK.

He also published "The Secrets of Macintosh's creation" (Makkintosshu Tanjou no Hiwa, マッキントッシュ誕生の秘話), which features interviews with both the founding members and other core developers.

He is also known for suggesting the addition of a speaker to the Wii controller after its initial announcement.,[2] and for being the writer of the exposition portion of the Ultraman Research Introduction (ウルトラマン研究序説).