I believe he also played a recurring Romulan character on Star Trek: TNG. Sad news.
Yeah, he played Commander Tomalok. Good character, good actor.
From Sci-Fi Wire:
Andreas Katsulas, the character actor known to SF fans as G'Kar on Babylon 5 and a familiar face from Star Trek and other SF&F TV shows, died Feb. 13 of lung cancer in Los Angeles, his agent, Donna Massetti, confirmed to SCI FI Wire. He was 59.
Katsulas, a longtime resident of Los Angeles, played the Narn ambassador G'Kar for five years in the syndicated cult TV series Babylon 5, starting in 1993. He reprised the role in subsequent Babylon 5 telefilms.
Katsulas was also no stranger to Trek fans, playing Romulan Cmdr. Tomalak in Star Trek: The Next Generation. His last appearance in a Trek series was as a Vissian captain on an episode of Enterprise.
Born in St. Louis, Katsulas held a master's degree in theater from Indiana University, his official Web site said. After performing in plays in St. Louis, New York and Boston, he went on to film roles in such movies as Michael Cimino's The Sicilian, which brought him to Los Angeles, then in Ridley Scott's Someone to Watch Over Me and Blake Edward's Sunset.
Katsulas moved to Los Angeles permanently in 1986 and found scores of television and film parts in everything from TV's Alien Nation and Max Headroom to the big screen's The Fugitive, in which he played the infamous one-armed man, and Executive Decision opposite Kurt Russell and Steven Seagal.
Information on memorial services was pending at press time. Patrick Lee, News Editor
And there's also this, from J. Michael Straczynski, the creator of Babylon 5:
Just over a year ago, Andreas Katsulas -- who loved smoking with a passion that cannot be described -- was diagnosed with lung cancer, which by then had already spread to other areas. He quit smoking at once and went on a healthy diet and vitamin program, but there was little hope of a good resolution even though the new regimen was very good for him. When we spoke about it, he laughed, and said, "Now that I'm dying I've never felt better!"
His spirits were always up and positive, putting everyone at ease about his condition, because...well, that's the kind of person he was.
A couple of months ago, he and his wife convened a dinner with me, Doug, and Peter Jurasik, which was filled with laughter and stories and good food. He wanted to know all the stories we never told him because, as he said, "Who am I going to tell?" So we did. Because we knew we were saying goodbye, and there would not be a second chance.
Last night, in the company of his wife and family, Andreas closed his eyes and went away.
He lived an amazing life...full of travel and wonder and good work...was part of the world renowned Peter Brook company...he saw the planet, loved and was loved, ate at great restaurants, smoked too many cigarettes...he lived a life some people would die for.
And, sadly, due to the last part of that equation...he did.
Memorial arrangements are still being worked out, but will doubtless be private.
Andreas is gone...and G'Kar with him, because no one else can ever play that role, or ever will.
I will miss him terribly.
J. Michael Straczynski