(written from a Production point of view)
Ellis may best be known for playing Michael Amador in the third season of the hit FOX television series 24. Among the actors he worked with on this series was his Star Trek movie co-star Zachary Quinto, as well as Penny Johnson, Albert Hall, Jamie McShane, Jack Kehler, Glenn Morshower, Colby French, Michael Cavanaugh, Jenette Goldstein, Tony Todd, and J.D. Cullum. Ellis has made guest appearances on several other shows, including The X-Files, Even Stevens, CSI, and Bones.
In addition, Ellis can be seen in such films as Paramount's Academy Award-winning Titanic (co-starring David Warner), Megiddo: The Omega Code 2 (with Jim Metzler and Guy Siner), Mr. & Mrs. Smith (also featuring Jennifer Morrison and Megan Gallagher), Goal! (starring Tony Plana), and Beowulf (co-starring Dominic Keating). Ellis also played a British officer in the 2003 blockbuster, Pirates of the Caribbean: The Curse of the Black Pearl (which featured another future Star Trek movie co-star Zoë Saldana, along with Lee Arenberg), and its hit 2007 sequel, Pirates of the Caribbean: At World's End (again with Arenberg).
Ellis is also a prolific voice-over actor and has contributed his voice to many video games, including two Star Trek games: Star Trek: Hidden Evil and Star Trek: Invasion, both of which feature Patrick Stewart as the voice of Jean-Luc Picard. Ellis and Stewart later did voice work for the video game X-Men Legends.
Among the many other video games featuring Ellis' vocal talents are StarLancer (also featuring the voice of Dominic Keating), EverQuest II (with Larry Cedar, Alan Dale, Paul Eiding, James Horan, John Kassir, Dwight Schultz, Daniel Riordan, Raphael Sbarge and Wil Wheaton), Star Wars: Knights of the Old Republic II: The Sith Lords (also with Raphael Sbarge), Ghost Recon 2 (also with Wil Wheaton), God of War II (with Paul Eiding, Alan Oppenheimer, Armin Shimerman, and Marc Worden), the Lord of the Rings: Battle for Middle-earth series, and several entries in the Call of Duty, SOCOM and Tomb Raider series.
Ellis most recently appeared in NBC's TV movie revival of the 1980s series Knight Rider. Susan Gibney and Bruce Davison also appeared in this movie, as did Star Trek movie auditioner Sydney Tamiia Poitier. He portrayed Ari Valentine, the Human alias of Greek god Ares, in the short lived drama series Valentine (2008), where he appeared alongside regulars Autumn Reeser and Patrick Fabian, and guest stars such as David Burke, Tim Ransom, and Noa Tishby.