He was born on July 12, 1920, in Whitehorse, Yukon, where his father had moved for the 1898 Klondike Gold Rush. His family moved to Dawson City, Yukon in 1921, where they lived until moving to Victoria, British Columbia in 1932. His mother, Laura Beatrice Berton (née Thompson) was a school teacher in Toronto until she was offered a job as a teacher in Dawson City at the age of 29 in 1907. She met Frank Berton in the nearby mining town of Granville shortly after settling in Dawson and teaching kindergarten. Laura Beatrice Berton's autobiography of life in the Yukon entitled I Married the Klondike was published in her later years and gave her, what her son Pierre describes as 'a modicum of fame, which she thoroughly enjoyed.'

Like his father, Pierre Berton worked in Klondike mining camps during his years as a history major at the University of British Columbia, where he also worked on the student paper The Ubyssey. He spent his early newspaper career in Vancouver, where at 21 he was the youngest city editor on any Canadian daily, replacing editorial staff that had been called up during the Second World War.

Berton himself was conscripted into the Canadian Army under the National Resources Mobilization Act in 1942 and attended basic training in British Columbia, nominally as a reinforcement soldier intended for The Seaforth Highlanders of Canada. He elected to "go Active" (the euphemism for volunteering for overseas service) and his aptitude was such that he was appointed Lance Corporal and attended NCO school, and became a basic training instructor in the rank of corporal. Due to a background in university COTC and inspired by other citizen-soldiers who had been commissioned, he sought training as an officer.

Berton spent the next several years attending a variety of military courses, becoming, in his words, the most highly trained officer in the military. He was warned for overseas duty many times, and was granted embarkation leave many times, each time finding his overseas draft being cancelled. A coveted trainee slot with the Canadian Intelligence Corps saw Berton, now a Captain, trained to act as an Intelligence Officer (IO), and after a stint as an instructor at the Royal Military College in Kingston, Ontario, he finally went overseas in March 1945. In the UK, he was told that he would have to requalify as an IO because the syllabus in the UK was different from that in the intelligence school in Canada. By the time Berton had requalified, the war in Europe had ended. He volunteered for the Canadian Army Pacific Force (CAPF), granted a final "embarkation leave", and found himself no closer to combat employment by the time the Japanese surrendered in September 1945.Berton moved to Toronto in 1947. At the age of 31 he was named managing editor of Macleans. In 1957, he became a key member of the CBC's public affairs flagship program, Close-Up, and a permanent panelist on the popular television show Front Page Challenge. That same year, he also narrated the Academy Award-nominated National Film Board of Canada documentary City of Gold, exploring life in his hometown of Dawson City during the Klondike Gold Rush. He then released an album in conjunction with Folkways Records, entitled The Story of the Klondike: Stampede for Gold - The Golden Trail.

Berton joined the Toronto Star as associate editor and columnist in 1958, leaving in 1962 to commence The Pierre Berton Show, which ran until 1973. It was on this show that in 1971 Berton interviewed Bruce Lee in what was to be the famous martial artist's only television interview. Berton's television career included spots as host and writer on My Country, The Great Debate, Heritage Theatre, The Secret of My Success and The National Dream.

Berton served as the Chancellor of Yukon College and, along with numerous honorary degrees, received over 30 literary awards such as the Governor General's Award for Creative Non-Fiction (three times), the Stephen Leacock Medal of Humour, and the Gabrielle Léger Award for Lifetime Achievement in Heritage Conservation. He is a member of Canada's Walk of Fame, having been inducted in 1998. In The Greatest Canadian project, he was voted #31 in the list of great Canadians.

In 2004, Berton published his 50th book, Prisoners of the North, after which he announced in an interview with CanWest News Service that he was retiring from writing. On October 17, 2004, the $12.6 million CAD Pierre Berton Resource Library, named in his honour, was opened in Vaughan, Ontario.

He had lived in nearby Kleinburg, Ontario, for about fifty years.

Berton raised eyebrows in October 2004 by discussing his forty years of recreational use of marijuana on two CBC Television programs, Play and Rick Mercer Report. On the latter show he gave a "celebrity tip" on how to roll a joint.

Berton died at Sunnybrook hospital in Toronto, reportedly of heart failure, at the age of 84 on November 30, 2004.

His childhood home in Dawson City, now called Berton House, is a writers' retreat. Established writers apply for three-month long subsidized residencies there; while in residence, they give a public reading in both Dawson City and Whitehorse. The Berton House Retreat is sponsored by a charitable foundation set up to support it and by the Klondike Visitors Association; the administrator is Elsa Franklin. Franklin was Berton's long-time editor and agent.

Established in 1994, the Pierre Berton Award is presented annually by Canada's National History Society for distinguished achievement in presenting Canadian history in an informative and engaging manner. Berton was the first recipient and agreed to lend his name to future awards.