McCormack is best known for his work on the sitcom "Will & Grace" and in the TV movie "Who is Clark Rockefeller?"
"Perception" marks McCormack's third project with TNT. He previously starred in the 2009 series "Trust Me" and co-produced the 2007 pilot "Imperfect Union." He will also act as a producer on "Perception," the cable network said.
In his latest project, he will play Dr. Geoffrey Pierce, an eccentric neuroscientist who "uses his unique outlook to help the federal government solve complex cases," TNT said.
"Eric McCormack is an intelligent, intuitive and versatile actor who is adept at both comedy and drama," Michael Wright, executive vice president and head of programming for TNT, TBS and Turner Classic Movies, said in a statement. "We're very excited to work with him again and can't wait to see what he brings to the fascinating character of Dr. Geoffrey Pierce."