Tadao Nagahama was a Japanese director of both anime and puppet television shows, born on September 26, 1936. His career, though relatively short, left a significant mark on the anime industry of the 1970s, particularly within the super robot genre. He passed away on January 14, 1980, at the age of 43.

Nagahama's background was in theater and puppetry, which deeply influenced his approach to animation. He began his theatrical career in junior high school, both directing and acting on stage. He later studied drama at Nihon University College of Art and worked in the production department of the puppet theater troupe Hitomi-za, where he was assigned to direct puppet shows for television. In 1965, he joined A Production, an animation studio, and began directing TV anime.

His early directorial work included episodes for series like Obake no Q-tarō and Perman. However, his first major success came as the director of the sports anime Star of the Giants, which began airing in 1968 and became a national hit, contributing significantly to the popularity of baseball in Japan. After a brief departure from anime to work on commercial production, Nagahama returned to the industry in 1975.

Nagahama is best known as the director of the Robot Romance Trilogy, a series of three super robot anime produced by Toei Company and animated by Sunrise (then known as Nippon Sunrise). This trilogy consisted of Chōdenji Robo Combattler V (1976-1977), Chōdenji Machine Voltes V (1977-1978), and Tōshō Daimos (1978-1979). He served as the general director and sound director for all three series. These works were credited with adding deep human drama, romanticism, and complex characterizations to the super robot genre, moving beyond simple monster-of-the-week battles to explore themes of family, social inequality, and the psychology of the enemy. For instance, the central conflict in Voltes V involves a race war on the alien planet Boazan, and the main antagonist, Prince Heinel, is portrayed with sympathetic depth.

Nagahama's theatrical background heavily informed his directing style. He emphasized acting, often gathering animators to recite scripts and providing detailed guidance to voice actors to ensure their performances matched the on-screen character expressions. This led to him being credited as a sound director on many of his series. He also focused on screen composition, lighting, and the effective use of props and special moves, such as Voltes V's signature "V" slash with its sword, the Tenkūken. He also wrote lyrics for several anime theme songs under the pen name Akira Aoi.

Beyond the Robot Romance Trilogy, his directorial credits include Brave Raideen (1975-1976), which was his first robot anime and where he replaced Yoshiyuki Tomino midway through the series. He also directed Future Robot Daltanious (1979-1980) and was the initial general director for the first thirteen episodes of the historical drama The Rose of Versailles (1979-1980). His final project was as the Japanese chief director for the joint Japan-France production Ulysses 31 (1981), though he passed away after the completion of the first episode.

Nagahama is noted for having a significant influence on other creators, including Yoshiyuki Tomino, who worked under him and later created the Gundam series. His work on the Robot Romance Trilogy is considered foundational, establishing many of the narrative and dramatic conventions that would come to define the super robot and later real robot genres. He died suddenly from fulminant hepatitis during the production of Ulysses 31.