Green began his journalism career in 1995 as an editor at the satirical weekly The Onion. From 2000 to 2001, he was a staff writer at The American Prospect. He then joined The Washington Monthly, where he worked as an editor from 2001 to 2003. Green has also contributed articles to Slate and The New Yorker.
Green has been with The Atlantic Monthly since September 2003. During that time his work has been anthologized in collections ranging from Best American Political Writing 2009 to The Bob Marley Reader. Among his more notable writings for The Atlantic Monthly are a November 2006 cover story on Hillary Rodham Clinton and a November 2004 story on George W. Bush presidential adviser Karl Rove. Green also wrote an article for The Atlantic in October 2007 exploring the feasibility of the announced presidential campaign of the comedian Stephen Colbert.
In 2007, Politico reported that a negative story written by Green on the Hillary Rodham Clinton presidential campaign for GQ magazine was killed after her camp threatened access to the New York Senator's husband, President Bill Clinton, who was slated to appear on the magazine's December 2007 cover. In September 2008, after Clinton had ended her candidacy, Green wrote an article in The Atlantic Monthly detailing the in-fighting within the Clinton campaign. The article was supplemented by memos he had obtained from current and former Clinton staffers and outside consultants to her presidential campaign.