Cockburn was born in Ireland and grew up in County Cork, Ireland. His parents were the well-known socialist author and journalist Claud Cockburn and his third wife Patricia Byron, née Arbuthnot (who also wrote an autobiography, Figure of Eight). He was educated at Glenalmond College, Perthshire, and Trinity College, Oxford.

Cockburn married Janet Montefiore, daughter of Rt. Rev. Hugh Montefiore, and has two children, Henry Claud and Alexander. He has two brothers, Alexander Cockburn and Andrew Cockburn who are also journalists, and a half-sister, mystery writer Sarah Caudwell. Journalists Laura Flanders and Stephanie Flanders are his half-nieces, daughters of his half-brother in law Michael Flanders, and actress Olivia Wilde, is his niece, daughter of his sister in law Leslie Cockburn.

Cockburn has written three books on Iraq. One, Out of the Ashes: The Resurrection of Saddam Hussein, was written with his brother Andrew Cockburn prior to the war in Iraq. The same book was later re-published in Britain with the title Saddam Hussein: An American Obsession. Two more were written by Patrick alone after the U.S. invasion, following his award-winning reporting from Iraq. The first, The Occupation: War and Resistance in Iraq (2006) mixes first hand accounts with reporting, Cockburn's book is critical of the invasion as well as the Salafi fundamentalists who comprise much of the resistance. The Occupation was nominated for the 2006 National Book Critics Circle award for nonfiction. The second, Muqtada: Muqtada al-Sadr, the Shia Revival, and the Struggle for Iraq was published in 2008. Muqtada is a journalistic account of the recent history of the religiously and politically prominent Sadr family, the rise of Muqtada, and the development of the Sadrist movement since the 2003 U.S. invasion.

Cockburn's memoir is The Broken Boy (2005), a memoir of his childhood in 1950s Ireland, as well as an investigation of the way polio was handled - Cockburn himself caught and survived polio at the time. He has also published a collection of essays on the Soviet Union, titled Getting Russia Wrong: The End of Kremlinology (1989). He also writes for CounterPunch and the London Review of Books.

Patrick Cockburn won the Orwell Prize for Journalism in 2009 for his coverage of Iraq and his son's schizophrenia.

In 2010, Patrick Cockburn won a Peace through Media award from the International Council for Press and Broadcasting at the sixth annual International Media Awards