Adams worked as Assistant Editor at The Magazine of Fantasy & Science Fiction from May 2001 to December 2009. In January 2010 he left F&SF to edit Lightspeed Magazine, an online science fiction magazine which launched June 1, 2010. In March 2011 he took charge of its sister magazine, Fantasy Magazine. In June 2012, Adams and Creeping Hemlock Press successfully closed a $7,500 Kickstarter campaign[1] for funding Nightmare Magazine, the first issue of which released October 2012. Originally the co-publisher and editor-in-chief, Adams now serves as publisher.
In November 2011 Adams purchased Lightspeed and Fantasy Magazine from Sean Wallace of Prime Books.[2] With the January 2012 issue, the first published under Adams's ownership, the content of both magazines was combined under the Lightspeed masthead, and Fantasy Magazine was discontinued as an entity.[3] The Fantasy Magazine staff was also absorbed into Lightspeed.
In 2015, Adams became the editor-at-large of John Joseph Adams Books in partnership with Houghton Mifflin Harcourt.[4]
His anthology The Living Dead was nominated for a World Fantasy Award[5] and named one of the "Best Books of the Year" by Publishers Weekly. He has been called "The reigning king of the anthology world" by Barnes & Noble.com, and in 2011 he was named one of "100+ Geeks to Follow on Twitter" by TechRepublic. He is a finalist for the 2011 Hugo Award for Best Professional Editor, Short Form, and his magazine, Lightspeed Magazine, is a finalist for best semiprozine.[6]
In 2017, John was nominated for a World Fantasy Award for Best Anthology for The Best American Science Fiction and Fantasy 2016.