J. Michael Straczynski, who created the series, announced the news via Facebook. "I regret that I must convey the sad news that Michael O'Hare passed away today," Straczynski wrote Friday. "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."
O'Hare was a regular on Babylon 5 in the first season, and appeared as Sinclair in Seasons 2 and 3 of the series as well. He also appeared in the original Broadway production of A Few Good Men, and his other television credits included Law & Order, L.A. Law and One Life to Live.