I first discovered Daniel in the Babylon 5 spin-off "Crusade", playing the first officer of Lt. Matheson. It ran only 13 episodes (fuck you very much, TNT bastards - "We Know Bullshit!" ... If a single person working for TNT had a brain, the series would have had a full 5 years ... bitter? me?), after which he had roles in both Voyager and Enterprise. He had a recurring role on Angel as Gavin Park, before joining the hit series Lost. Yes, that's the Lost series which has Babylon 5 star Mira Furlan in its cast.
Daniel's Official Website.