He gained fame for his role as Dr. Michael Gallant, a character that debuted in the eighth season (2001) of the NBC Universal Television medical drama ER. He left ER after the 2003-2004 season. In 2004, he went on to star in the short-lived police drama Hawaii as former Chicago Police Department Detective John Declan, who transferred to an elite crime unit of the Honolulu Police Department. Atkins continued to make guest appearances in both the 2004-2005 and 2005-2006 seasons of ER, with his character returning on leave from duty in Iraq as a U.S. Army physician. His character was killed in Iraq at the end of the 2005-06 season. Atkins also portrayed the recurring character Gary Navarro in the acclaimed series The 4400, Navarro is a telepath.
He has appeared as Assistant United States Attorney Rivers in the CBS drama The Good Wife. In 2009 he appeared in season 4, episode 25 of Criminal Minds - "To Hell..." as Sgt. William Hightower. Atkins has also guest-starred in season 8 of CSI:Miami.