Jonathan Kimble "J.K." Simmons is an American actor and voice actor who is best known for his roles as Dr. Emil Skoda in the Law & Order television franchise, Vernon Schillinger on the HBO drama series Oz from 1997 to 2003, Tenzin in the Avatar: The Last Airbender spin-off series The Legend of Korra, and Kai, the main antagonist of DreamWorks' Kung Fu Panda 3. He is also well-known as the current voice of the Yellow M&M in the M&M's commercials since 1996.
For Disney, he voiced Seizaemon in Studio Ghibli's Pom Poko, Martin Smarty in Kim Possible, J.B. in Phineas and Ferb, J. Jonah Jameson in Ultimate Spider-Man, Avengers Assemble, and Hulk and the Agents of S.M.A.S.H. (a role he previously played in Sam Raimi's Spider-Man trilogy), Stanford Pines in Gravity Falls, and Mayor Lionheart in the 2016 animated film Zootopia. He also played Siskel in the 1994 Touchstone Pictures film The Ref, Buffalo Bill Cody in Hidalgo, and Garth Pancake in The Ladykillers.