Newitz was born in 1969, the daughter of two English teachers — her mother teaching high school and her father at community college — and grew up in Irvine, California. She once called herself "biethnic" because her father is Jewish and her mother is a white Southerner and former Methodist.

She graduated from Irvine High School, and in 1987 moved to Berkeley, California. In 1996, Newitz started doing some of her own freelance writing, and in 1998, she received a PhD in English and American Studies from UC Berkeley, with a dissertation on images of monsters, psychopaths, and capitalism in twentieth century American popular culture (later published as a book ). She worked briefly as an adjunct professor, and in 1999 became a fulltime writer and journalist.

In 2002, she was awarded a Knight Science Journalism Fellowship, and was a research fellow at Massachusetts Institute of Technology. From 2004-2005 she was a policy analyst for the Electronic Frontier Foundation, and from 2007-2009 she was on the board of Computer Professionals for Social Responsibility.

She is partners with author Charlie Anders. The couple co-founded other magazine, a tri-annual periodical which ran from 2002 to 2007, and was described as "pop culture and politics for the new outcast". In 2008, Gawker media asked Newitz to start a blog about science and science fiction, which was dubbed io9. Newitz has remained editor-in-chief since its founding, and in 2010, io9 was named one of the top 30 science blogs by The Times.

In 2007, Newitz argued against the Notability guidelines in her Techsploitation column, saying: "nothing is too minor to be in it. Everything should be noteworthy."

Newitz's work has been published in Popular Science, Wired, Salon.com, New Scientist, Metro Silicon Valley, the San Francisco Bay Guardian, and AlterNet. She is the editor-in-chief at io9, a science blog launched in 2008 by Gawker Media. She has discussed her work on CNN, The New York Times, NPR, G4, the BBC, and the CBC,a written for the San Francisco Chronicle and Washington Post, and she is a regular lecturer at various colleges and conferences.

Periodicals

• (creator, founding editor) io9.com, 2008
• (co-founder) other magazine, 2002
• (co-founder) Bad Subjects, 1992, touted as the first leftist publication on the Internet (originally published via gopher)

Articles

• "Five Ways The Google Book Settlement Will Change The Future of Reading (io9.com, 2010)
• "Why Did Nearly All Life On Earth Die 250 Million Years Ago?" (io9.com, 2010)
• "When Will White People Stop Making Movies Like Avatar?" (io9.com, 2009)
• "How I Bought Votes on Digg" (Wired News, 2007)
• "Code of the Caveman -- New DNA Mapping Techniques Reveal the Secrets of Extinct Neanderthals" (Wired, 2006)
• "The RFID Hacking Underground" (Wired, 2005)
• "Why We All Need Pornography" (New Scientist, 2005)
• "The Conlangers Art -- Language Inventors Talk a New World Into Being One Language at a Time" (The Believer, 2005)
• "Sorry, Your Vote Has Been Lost, Hacked, Miscast, Recorded Twice -- The Trouble with E-voting" (Popular Science, 2004)

Books

• (co-editor, with Charlie Anders) She's Such a Geek (Seal Press, 2006)
• Pretend We're Dead: Capitalist Monsters in American Pop Culture (Duke University Press, 2006)
• The Bad Subjects Anthology (New York University Press, 1998)
• White Trash: Race and Class in America (Routledge Press, 1997)

Short stories

• The Great Oxygen Race (Hilobrow magazine, 2010)
• The Gravity Fetishist (Flurb magazine, 2010)