The new series, created by Prison Break producer Matt Olmstead, will focus on a squad of US Marshals who hunt down escaped fugitives.
Knepper told Fancast: "My first reaction was... 'I won't do it if they kill T-Bag'. And I'm doing it, so I guess I just gave it away that they don't kill him! My next thought was, 'This is a stupid thing for me to do, because I've finished with this guy and I'm moving on'. So I wasn't sure at first."
The actor explained that fan reaction to the news convinced him to play the vicious criminal again.
"Word got out that it might happen, and I got e-mails from all over the world," he claimed. "I realised the power [that] this character has for so many people around the world, so I'm thinking I'll survive it."
A&E has ordered 13 episodes of Breakout Kings.