Dunford replaced Marine Corps Gen. John R. Allen during a change of command ceremony attended by U.S., NATO and Afghan officials, the ISAF said in a news release.
"Today is not about change, it's about continuity," Dunford said. "I'll endeavor to continue the momentum of the campaign and support the people of Afghanistan as they seize the opportunity for a brighter future."
Allen led coalition troops for 19 months, beginning in July 2011, making him the longest-serving ISAF commander in the 11-year war, ISAF said.
Dunford previously served as assistant commandant of the U.S. Marine Corps; assistant division commander for the 1st Marine Division; director of operations division for plans, policies and operation at Marine headquarters; and commanding general of the Marine Forces Central Command.