Among his credits include the voice of Spike Spiegel in the anime show Cowboy Bebop and Mugen in Samurai Champloo. He voiced Roger Smith from The Big O, Orochimaru and Zabuza in the Naruto anime, X-Men's Wolverine in numerous games, as well as in the animated series Wolverine and the X-Men, the animated movie Hulk Vs, The Super Hero Squad Show and Marvel Anime: X-Men. He also provided the video game voice of Jack Cayman, the main character of MadWorld, Tank Dempsey, the comic relief of Call of Duty: World at War and Call of Duty: Black Ops zombie modes, Professor Galvez in Metal Gear Solid Peace Walker, and Grayson Hunt, the main protagonist of Bulletstorm and Gorim, Oghren, and First Enchanter Irving in the 2009 video game Dragon Age: Origins.
In September 2000, Blum voiced the role of TOM, the robotic host of Toonami shown on Cartoon Network (replacing Sonny Strait), as the second through 4th incarnations of the character right up to the block's cancellation on September 20, 2008 delivering the final lines uttered on the block, echoing his early role of Cowboy Bebop's Spike Spiegel, to recent revival of the block on May 26, 2012. He is also the voice of Amon in The Legend of Korra and 7-Eleven's "Oh Thank Heaven" television and radio advertisements and for his work with Vic Mignogna in a scratch-made sound bite series parodying Anheuser-Busch's "Real Men of Genius" radio ad campaign, titled "Real Fans of Genius". Revealed by Blind Ferret Entertainment on November 15, 2012, it was announced that Blum will be playing Harry, "the Homeless Bum," in Least I Could Do: The Animated Series.
He is also well known in American-based animation; as the voices of Heatblast, Ghostfreak, and Vilgax in the Ben 10 franchise, Jamie in Megas XLR, Yakky Doodle and Clamhead in Harvey Birdman, Attorney at Law, Smytus in My Life as a Teenage Robot, and his voice portrayals of Starscream in Transformers: Prime and Count Vertigo in DC Showcase: Green Arrow as well as in Young Justice, The Red Skull, Beta Ray Bill and Wolverine in The Avengers: Earth's Mightiest Heroes and as Melbourne O'Riley in What's New, Scooby Doo?.
On June 5, 2012, he was awarded a Guinness World Record for being the most prolific video game voice actor, having 261 credited appearances on May 10. He is also considered as "the king of anime", among fans and the number of credit appearances. Additionally, Blum worked as a writer in English adaptations of Naruto, Digimon: Digital Monsters and MegaMan NT Warrior. He is also a Jewish Spiritualist and is married.
See his massive voice acting credits list .