The former U.S. national team attacker will help fill the void left by Chris Pontius' injury for the Black-and-Red.
Rolfe, 31, was in his second stint with the Fire after leaving the team in 2009 for Danish Superliga club Aalborg BK. Upon his return in 2012, Rolfe was named the team's MVP and led the Fire in scoring.
“Chris brings great technical ability as well as national team and European experience to our club,” said D.C. United General Manager Dave Kasper in a club release. “He plays with a high soccer IQ and will give us more options in our attack. As a well-liked and respected veteran in our league, we look forward to him joining the team.”
Rolfe made his debut with the United States national team in November 2005, and has 10 caps overall, most recently in 2009.
With Chris Pontius still out indefinitely, Rolfe will help contribute in attack for United, which has started the season with two losses and one draw in three matches.