Halder has appeared as a guest star in Highlander: The Series, Millennium, and Hope Island as well as playing roles in the X-Files, The Outer Limits, Dead Man's Gun and Poltergeist. He also has the role of recurring Stargate SG-1 character Cronus. He is currently involved in voice-work for cartoons, like in Eon Kid where he is a voice actor for Gaff. He usually plays the role of an eccentric doctor/professor, a kindly older man/mentor, or a hard and malicious man. He has also taught stage fight combat at the National Theatre School of Canada in Montreal, and has choreographed numerous "safe" fight scenes for both stage and camera. In the Death Note live action movie he is the English dub voice actor of Watari; coincidentally in the Death Note anime, he voices Watari's counterpart, Roger Ruvie.