"The Washington Post" editor Ben Bradlee hired Gellman as a full-time staff writer in 1988 to cover Washington, D.C. courts, including the trial of former D.C. mayor Marion Barry. Gellman went on to become Pentagon correspondent during the 1991 Persian Gulf War, the U.S. intervention in Somalia and the social upheavals relating to the status of homosexuals in the military and the assignment of women to combat roles. In 1994, he moved to Jerusalem as bureau chief, covering peace negotiations, the assassination of Yitzhak Rabin, and the ascent of Benjamin Netanyahu. He returned to Washington as diplomatic correspondent in late 1997, covering Secretary of State Madeleine Albright and the collapse of the United Nations Special Commission (UNSCOM) effort to disarm Iraq.