The actor plays an FBI agent working on a multi-agency, counter-terrorism team.
"I had done 'The Practice' for so many years," McDermott told United Press International. "This was just all new people and it was a different environment. It was fun. The material was so good, so it didn't matter to me where it was."
McDermott and other cast members were axed from "The Practice" in 2003 to increase viewers and cut costs. But, the drama was canceled after the 2003-2004 season.
McDermott, who was on the show seven years, said he harbors no ill will toward his former employers.
"I'm very grateful that I had that time because a lot of good actors don't ever get the chance to do that," he noted. "It was kind of funky the way it ended, but I just try to remember the good. It's like a relationship."
"The Grid" premieres July 19 on cable's TNT.