Berger majored in English literature and art history at Brooklyn College, and upon her graduation in 1979, she entered the comics profession as an assistant to editor Paul Levitz at DC. She later became Levitz's editor when he was writing Legion of Super-Heroes. More interested in horror comics, she soon became editor of House of Mystery, and was instrumental in nurturing Alan Moore's Swamp Thing book, taking over the editing from co-creator Len Wein. She also edited Amethyst, Princess of Gemworld. She later helped bring Neil Gaiman's work to a mass audience by having him write The Sandman. The success of these titles, and her willingness to help the writers who worked with her push the envelope of what could be done in mass-circulation comic books, led to the creation of the mature-reader Vertigo line in 1993. Her critically and popularly successful titles under that imprint include Fables, Hellblazer, The Invisibles, 100 Bullets, Preacher, V for Vendetta, and . Berger is married to Richard Bruning, who also formerly worked at DC. In 2007 Berger was named supervising editor of Minx, a new comic book imprint published by DC. Minx published comics and graphic novels aimed at teenage girls until they were cancelled in 2008. On December 3, 2012, she announced that she would be stepping down from her post as Executive Editor & Senior Vice President of DC Entertainment’s Vertigo imprint and that she would remain on through March 2013 to assist in the transition to a new editorial team. The New York Times profiled Berger and her departure from Vertigo in an article entitled "Comics' Mother of 'The Weird Stuff' is Moving On". In February 2017Dark Horse Comics announced that Karen Berger would be overseeing a new line of creator owned comics published by Dark Horse under the imprint: Berger Books. Berger Books' first print publication was Berger Books Free 2018 Preview dated November 2017. Berger Books first full comic was Hungry Ghosts #1, on sale in comic book shops on January 31, 2018. As of February 2019 Berger Books publishes several titles including Incognegro and a prequel Incognegro: Renaissance both written by Mat Johnson, She Could Fly written by Christopher Cantwell , The Seeds written by Ann Nocenti, and LaGuardia written by Hugo Award winner Nnedi Okorafor.
