The news was broken by B5 creator J. Michael Straczynski via Patricia Tallman: “I regret that I must convey the sad news that Michael O’Hare passed away today. He suffered a heart attack on Sunday and was in a coma until his passing this afternoon. This is a terrible loss for all B5 fans and everyone involved with the show wishes to convey their condolences to the O’Hare family. He was an amazing man.”
As well as starring in the sci-fi series, O’Hare appeared in numerous theatrical shows, including Man and Superman, and A Few Good Men.