Karl will play Sgt. Mike Dodds, son of Deputy Chief William Dodds (Peter Gallagher).
In an interview with TV Guide, executive producer Warren Leight said, "It doesn't look like someone is going to pick up the slack, which mean these three detectives will have to have a new boss who doesn't know anything about the job they do. Finn has been there 17 years and will deal with someone who just got there giving him orders…It'll be interesting watching the squad adapt or not adapt."
Karl earned a Tony nomination for his performance in Rocky. He has appeared in Legally Blonde, Wicked, Saturday Night Fever, Jersey Boys, 9 to 5, The Mystery of Edwin Drood and On The Twentieth Century.
"Law & Order: SVU"'s two-hour Season 17 opener premieres Sept. 30 at 9 PM ET on NBC.