(written from a Production point of view)
Besides Enterprise, he has made appearances on The Pretender (in an episode with Lawrence Pressman), Buffy the Vampire Slayer (starring James Marsters), Curb Your Enthusiasm (with Shelly Desai), The District (with Roger Aaron Brown, Scott MacDonald, Frank Novak, and John Savage), Without a Trace (with Enrique Murciano), and Weeds (with Ron Canada, Cody Klop, Andy Milder, and Franc Ross). He also appeared in the TV movies Norma Jean & Marilyn (1996, starring Ashley Judd, Jeffrey Combs, Steven Culp, Alex Henteloff, and John Rubinstein) and The Pentagon Wars (1998, starring Kelsey Grammer and also featuring Bruce French, Randy Oglesby, and Richard Riehle).
The majority of his credits, however, have been voiceover roles. Both he and Dwight Schultz served as additional voices for the popular anime feature Princess Mononoke. In 2002, he lent his voice to the film Spirit: Stallion of the Cimarron, as did James Cromwell, Matt Levin, Richard McGonagle and Charles Napier. His voice can also be heard in multiple video games, including Final Fantasy X, Final Fantasy X-2, and Everquest II.
Paul also wrote, produced, and starred in the 2004 short subject King of the Moon, in which he played Buzz Aldrin. The following year, he wrote, directed, and appeared in another short entitled I'm Not Gay.
Paul recently wrote and starred in the comedy series Hollywood Residential, which began airing on the Starz network in January 2008. This series revolves around a fictional celebrity home makeover show hosted by Paul's character, a frustrated, under-achieving actor hoping to further his career. His co-host on the series is played by Lindsey Stoddart, who, like Paul, was a guest star on Enterprise. One of the homes featured on this series was Star Trek actor John Cho's. 
In 2009, Paul appeared in the filmThe Informant!, which starred former Enterprise regular Scott Bakula.