[2] Seago's television career includes appearances on Hunter, Star Trek: The Next Generation (episode: "Loud as a Whisper")[3] and The Equalizer as well as involvement in the children's show, Rainbow's End.

He was later cast by David Byrne for the German production of The Forest (1989), because he was so impressed with Seago's performance.

[3] He also had a significant role in Beyond Silence, a German film about a hearing girl growing up with deaf parents, directed by Caroline Link.

His roles there have included The Ghost of Hamlet's Father in Hamlet, Ned Poins in Henry IV, Part I and Henry IV, Part II, Marcellus Washburn in The Music Man, Bob Ewell in To Kill a Mockingbird, Duke Senior in As You Like It, King Cymbeline in Cymbeline, Little John in "The Heart of Robinhood", and Wolf in Into the Woods.

He also co-produced the PBS television show, Rainbow's End, which won an Emmy Seago spoke candidly about the effect his deafness has had on his life and work in the book Chronicles of Courage: Very Special Artists written by Jean Kennedy Smith and George Plimpton and published by Random House.