He also starred in the Disney XD sitcom I"m in the Band as Derek Jupiter until its 2011 cancellation. Valentine has been seen in films such as Tim Burton"s Mars Attacks! and Foreign Correspondents and has guest-starred on shows such as House Doctor of Medicine, Monk, Just Shoot Maine, Will and Grace, Dharma & Greg, Supernatural,and Charmed. He appeared as an art critic in Ringo Starr"s Discover Card "Private Issue" commercials in 1995.
Valentine hosted the Sciences-Fi Channel"s reality show Estate of Panic.
He voiced the character of Alistair in Dragon Age: Origins as well as the character of Harry Flynn in the video game Uncharted 2: Among Thieves. He also was Mr. Moore in the 2010-aired Disney Channel movie Avalon High, which was his second Disney Channel Movie (the first being Don"t Look Under the Bed), and was also in Wizards of Waverly Place: The Movie.
In 2013, along with Kevin Chamberlin, he played a villain on Teen Beach Movie, which starred Ross Lynch and Maia Mitchell.