St. Clair attended the American University in Washington, D.C.,[2] majoring in English and history. He has worked as an environmental organizer and writer for Friends of the Earth, Clean Water Action Project, and the Hoosier Environmental Council.
In 1990, he moved to Oregon to edit the influential environmental magazine Forest Watch. In 1994, he joined journalists Alexander Cockburn and Ken Silverstein on CounterPunch. He co-edited CounterPunch from 1999 to 2012 with Cockburn. From 2012 to the present, St. Clair is the editor-in-chief.
In 1998, he published his first book, with Cockburn, Whiteout: the CIA, Drugs and the Press, a history of the CIA's ties to drug gangs from World War II to the Mujahideen and Nicaraguan Contras. This was followed by A Field Guide to Environmental Bad Guys (with James Ridgeway), and with Cockburn, Five Days that Shook the World: Seattle and Beyond, and Al Gore: a User's Manual. St. Clair wrote the books, Been Brown So Long It Looked Like Green to Me: the Politics of Nature, Grand Theft Pentagon, and Born Under a Bad Sky: Notes from the Dark Side of the Earth. His new book, Bernie and the Sandernistas: Field Notes from a Failed Revolution, is available in print and as an ebook.
Books
Whiteout: The CIA, Drugs and the Press (1998) (with Alexander Cockburn) ISBN978-1-85984-258-4
A Field Guide to Environmental Bad Guys (1999) (with James Ridgeway) ISBN978-1-56025-153-8
Five Days That Shook The World: The Battle for Seattle and Beyond (2000) (with Alexander Cockburn) ISBN978-1-85984-779-4