Thomas Hailer was a German actor and voice actor, active in his craft until his death in 2014. He was born on January 15, 1945, in Netzschkau, Germany, and passed away on August 22, 2014, in Berlin. Hailer's career was deeply rooted in the performing arts, beginning with his training at the Theaterhochschule in Leipzig. This education led to numerous stage engagements at theaters in cities such as Plauen, Zwickau, Erfurt, and Weimar. In 1975, he was brought to the Komische Oper Berlin by the renowned director Walter Felsenstein, further solidifying his place in the German theater scene. His work for the television of the German Democratic Republic included several leading roles and appearances in children's productions. He was particularly well-known for his long-standing stage partnership with Hans-Joachim Preil, with whom he performed on approximately 470 evenings. After the German reunification, he continued his stage work at the Komödie in Kassel and later became a permanent ensemble member of the Berliner Kriminal Theater from 2006 until his death. Beyond acting, Hailer also worked as a television host for the Mitteldeutscher Rundfunk (MDR) in the 1990s.

As a voice actor, Thomas Hailer built an extensive body of work, lending his voice to hundreds of characters in films, television series, and video games. According to the Deutsche Synchronkartei, a German dubbing database, he is credited with over 500 speaking roles. He was the regular German voice for notable figures such as Marvel Comics creator Stan Lee in several of his cameo appearances, including in films like Spider-Man 3 and the series Heroes. His filmography also includes dubbing roles in major Hollywood productions, providing voices for characters in X-Men: The Last Stand, The Amazing Spider-Man 2, Thor: The Dark Kingdom, and The Hangover.

In the realm of anime and animation, Hailer contributed his voice to several projects. He is confirmed to have voiced the character Rokujouji in the German dubbed version of the Black Jack OVA series, specifically for an episode that was dubbed in 2006 or 2007. Additionally, he provided a voice for the anime series Maison Ikkoku in 2006 and for a character in One Piece. His animation voice work also extended to Western productions, such as giving a voice to the character Automatix in a Berlinerisch dialect version of Asterix Conquers America and playing a police officer in an episode of the German version of SpongeBob SquarePants. In addition to his screen work, Thomas Hailer was also active in the production of German audio dramas and radio plays, contributing to series such as Benjamin Blümchen.