Dan Baum was born in Orange, New Jersey (or South Orange, New Jersey) to Seymour and Audrey Bernice (Goldberger) Baum. His father, Seymour, was an executive with Colgate-Palmolive. His mother, Audrey Bernice (Goldberger) Baum, was a social worker. Raised in South Orange, Baum graduated from Columbia High School in 1974. He graduated from New York University in 1978.

Over the years he worked for various publications as a journalist. He was staff writer for The New Yorker, for which he covered Hurricane Katrina. In addition to that famous magazine he was a reporter for The Wall Street Journal, The Asian Wall Street Journal, and The Atlanta Journal-Constitution. He also freelanced for various publications such as Rolling Stone, Wired, Playboy and Harper's Magazine. He also wrote several books: Gun Guys: A Road Trip, Citizen Coors: An American Dynasty and Smoke and Mirrors: The War on Drugs and the Politics of Failure.

In 1987 he married fellow reporter Margret L. Knox and they had one daughter, Rosa Baum. Over the next thirty-three years he and Margaret would makes their home in various places across the globe: Zimbabwe, France, Missoula, Mont., rural Mexico, Watsonville, Calif., and Boulder, Colorado (where he passed away).

For many years, Mr. Baum and Ms. Knox collaborated on writing projects that carried only Mr. Baum’s byline, though she was a full partner, he wrote on their website. They wanted their writing to speak with a strong individual voice, and they thought a double byline would undermine that goal.

He died on Oct. 8, 2020 at his home in Boulder, Colo., at 64. Cause of death was glioblastoma, a form of brain cancer.