Amann was a writer-producer on Castle before taking over showrunner duties from creator Andrew W. Marlowe in Season 7. He left the show before its eighth and final season in 2015. His previous producing credits include The X-Files, Crossing Jordan and Without a Trace.
On The Blacklist: Redemption, Amann will join a producing team that includes Blacklist EPs Jon Bokenkamp, John Eisendrath, John Fox, John Davis, Luke Reiter and JR Orci, according to TVLine, which first reported the news.
"It's going to be a great, super rich emotional decision that [Tom's] confronted with ... that's going to take him off and send him into that other world," Bokenkamp previously told TVGuide.com about the launch of the spin-off. "In terms of how and when he leaves, those episodes have yet to be written, but ... I think the fans and audience is going to see a really unique and realistic transition for him."