Jonathan Kimble "J. K." Simmons (born January 9, 1955) is an American actor.He is known for his roles as Dr. Emil Skoda on the NBC series Law & Order (and other Law & Order franchise series), neo-Nazi Vernon Schillinger on the HBO prison drama series Oz, Assistant Police Chief Will Pope on the TNT series The Closer, J. Jonah Jameson in Sam Raimi's Spider-Man trilogy, and the voice of Cave Johnson in the 2011 puzzle game Portal 2.

In 2014, he portrayed music instructor Terence Fletcher in Whiplash which earned him several accolades including a Golden Globe and an Academy Award nomination for Best Supporting Actor. From April 2012 to December 2014, he also voiced the character of Tenzin in The Legend of Korra.