Keanu Reeves has a limited but notable history within the realm of anime voice acting, primarily defined by his involvement in projects that expand upon the universe of The Matrix. His most significant and widely recognized role in anime is voicing the character Neo in The Animatrix. Specifically, he reprises his live-action role for the segment titled Kid's Story, a short film directed by Shinichirō Watanabe. This 2003 release was produced and co-written by the Wachowskis and served to bridge the narrative between the films The Matrix and The Matrix Reloaded. In Kid's Story, Reeves's Neo guides a teenager known as The Kid, helping him escape the simulated reality of the Matrix. The project is notable for bringing together the creative talent behind the live-action Matrix films with acclaimed anime creators, as Watanabe was already renowned for his work on the series Cowboy Bebop.

Beyond this specific credit, Reeves's career shows a clear trajectory toward projects that blend live-action and animation, particularly within the science fiction genre. He has lent his voice to numerous animated projects outside of the strict definition of anime, including major Hollywood productions like Toy Story 4 and DC League of Super-Pets. His voice work also extends to video games, most prominently as the character Johnny Silverhand in Cyberpunk 2077, a role that involves both voice and motion capture performance.

In a significant development that points to a more direct and expanded role in anime, Reeves is attached to star in and produce an anime series adaptation of his comic book, BRZRKR, for Netflix. In this project, he is set to provide the voice for the protagonist, an immortal warrior known as B. This venture represents a move from simply voicing a character in an existing anime universe to being a central creative force in developing a new one. Additionally, he has served as a narrator for documentary projects, including one on the life of legendary Japanese actor Toshiro Mifune, titled Mifune: The Last Samurai, further demonstrating his engagement with Japanese culture and cinema.