Junger was born in Belmont, Massachusetts, the son of Ellen Sinclair, a painter, and German-born Miguel Junger, a physicist. As a child he grew up in the neighborhood of the Boston Strangler which later inspired his efforts to write a book called A Death in Belmont about the event. He graduated from Concord Academy in 1980 and received a Bachelor of Arts degree from Wesleyan University in cultural anthropology in 1984.

In 1997, with the publication of his work, The Perfect Storm, he was touted as a new Hemingway, and helped usher a renewed interest in adventure non-fiction. He received a National Magazine Award in 2000 for "The Forensics of War," published in Vanity Fair in 1999. In early 2007 he reported from Nigeria on the subject of blood oil. With photographer Tim Hetherington, Junger received the DuPont-Columbia Award for broadcast journalism for his work on The Other War: Afghanistan, produced with ABC News and Vanity Fair, which appeared on Nightline in September 2008.

His most recent book, War, revolves around Junger's time spent with a United States Army platoon in Afghanistan. Junger used material gathered in the Korangal Valley of Afghanistan for the book and to create a documentary feature Restrepo which won the Grand Jury Prize for a domestic documentary at the Sundance Film Festival in 2010.

He lives with his wife Daniela in New York City, where he co-owns a bar called The Half-King.

The Perfect Storm

He found fame after writing the international bestseller The Perfect Storm: A True Story of Men Against the Sea. Published in 1997, it recounts the tale of the October 1991 "perfect storm" (in fact, the general use of the term originates from this book), focusing on the loss of the Gloucester fishing boat Andrea Gail off the coast of Nova Scotia and its six crew members, Billy Tyne, Bobby Shatford, Alfred Pierre, David Sullivan, Bugsy Moran, and Dale Murphy. It was subsequently made into a film by Warner Brothers.

At the time of the storm, Junger was recovering from a wound to the left leg that he suffered when working as a tree trimmer in the Boston area. His chainsaw had torn into his leg.

He established The Perfect Storm Foundation to provide cultural and educational grants to children, nationally, whose parents make their living in the commercial fishing industry.

A Death in Belmont

A Death in Belmont centers on the rape-murder of Bessie Goldberg, committed during the 1962—1964 period of the Boston Strangler crimes. Junger received the PEN/Winship award for the book. Although a different man was convicted, Junger raises the possibility that the real killer was Albert DeSalvo, who eventually confessed to committing several Strangler murders, but not Goldberg's. Goldberg's house was a mile and a quarter from the Junger family home, where Albert DeSalvo was doing construction work on the day Goldberg was killed. In fact, Junger stated in an interview that he grew up with a studio portrait of DeSalvo on his family's wall.

One day in 1962, before Junger was a year old, a photograph was taken. It shows Junger sitting on his mother's lap, and, standing behind them, two laborers who had just completed work on an extension to Junger's parents' house. Only two of the four subjects are looking directly at the camera: the baby and a stocky, smooth-haired man behind him, Albert DeSalvo.

Critics of the book have argued: i) Junger's story withholds the strong evidence against the convicted murderer, Roy Smith, presented by many witnesses who testified at the trial; and ii) Junger never reveals that Smith's conviction was upheld upon appeal to the Supreme Judicial Court of Massachusetts.

Critics further maintain: a) the description of Smith's day in Belmont omits the complete testimony by the official of the state agency that sent Smith to clean the victim's home, and the certainty of the time that the children coming home from school saw Smith cross the street as he left the Goldberg home; b) Smith lied pertaining to his time of arrival and time of departure from the Goldberg home; and c) other evidence stated in the opinion proves that Smith lied about cleaning the house and other important matters.

Junger's book raises the possibility that Smith's conviction was founded on circumstantial evidence, and in part on racism, because the prosecution's narrative of Smith's day in Belmont was built on witnesses who remembered seeing Smith chiefly because he was a black man walking in a white neighborhood. Smith had cleaned the victim's house on the day in question and left a receipt (for his work) with his name on the victim's kitchen counter. There was no physical evidence, such as bruises or blood, linking Smith to the crime. In 1976, he was granted commutation of his life sentence; however, before his release, Smith died of lung cancer.

In his final analysis in A Death in Belmont, Junger can draw no conclusions about the guilt or innocence of Smith or DeSalvo. The victim's daughter has vigorously disputed Junger's suggestion that Smith might have been innocent.

Fire

Fire is a collection of articles dealing with dangerous regions of the world or dangerous occupations. It is most notable for its chapter "Lion in Winter" in which Junger interviews Afghan Northern Alliance leader Ahmad Shah Massoud, the Lion of the Panjshir, a famed resistance fighter against first the Soviets and then the Taliban. Junger was one of the last Western journalists to interview Massoud in depth. The bulk of this interview was first published in March 2001 for National Geographic's Adventure Magazine, along with photographs by the renowned Iranian photographer Reza Deghati. Massoud was assassinated on September 9, 2001. Junger's portrait of Massoud gives one insight into how differently Afghanistan might have fared in the post-9/11 invasion had Massoud lived to help reclaim the country from the Taliban. Fire also details the conflict diamond trade in Sierra Leone, genocide in Kosovo and the hazards of fire-fighting in the Idaho wild.

Restrepo

In 2009 Junger made his first film, the documentary feature Restrepo, as director with photographer Tim Hetherington. The two worked together in Afghanistan on assignment for Vanity Fair. Junger and Hetherington spent a year with one platoon in the Korangal Valley, which is billed as the deadliest valley in Afghanistan. They recorded video to document their experience, and this footage went on to form the basis for Restrepo. The title refers to the outpost where Junger was embedded, which was named after a combat medic, Pfc. Juan Restrepo, killed in action. As Junger explained, "It’s a completely apolitical film. We wanted to give viewers the experience of being in combat with soldiers, and so our cameras never leave their side. There are no interviews with generals; there is no moral or political analysis. It is a purely experiential film." Restrepo, which premiered on the opening night of the 2010 Sundance Film Festival, won the grand jury prize for a domestic documentary. The actor David Hyde Pierce presented the award in Park City, Utah. Junger self-financed the film.

War

The visits from June 2007 to June 2008 to eastern Afghanistan to the Korangal Valley with Tim Hetherington resulted not only in their reports and pictures published in Vanity Fair in 2008 and the film Restrepo (2010), but also in Junger's best-selling book War (2010), which rewrites and expands upon his Vanity Fair dispatches.