Brady was born in Sheepshead Bay, Brooklyn. His career in journalism started working as a copy boy for the Daily News, where he worked while attending Manhattan College. He graduated in 1950. He left the paper to serve in the United States Marine Corps during the Korean War. During the war, he was a member of the 2nd Battalion, 7th Marines first leading a rifle platoon and later acting as an executive officer of a rifle company at one point serving under John Chafee. The majority of his service took place in the North Korean Taebaek Mountains during the fall and bitterly cold winter of 1951 and 1952. During this time he was also promoted to First Lieutenant. Brady was awarded the Bronze Star with the Combat V (recognizing an award resulting from combat heroism) in November 2001 for his actions on May 31, 1952 in a firefight with Chinese forces near Panmunjom.
Brady wrote extensively about his experiences as a Marine in Korea, including his 1990 autobiography, The Coldest War, which was a Pulitzer Prize finalist. Other books include the 2003 novel The Marine, as well as the non-fiction books The Scariest Place in the World published in 2005 and the 2007 book Why Marines Fight. Over the years, Brady spoke to groups of veterans about what he described as a "forgotten war", one where he went to Korea as an immature 23-year-old, and "Nine months later when I left, I was a grown-up and a pretty good Marine officer." Hero of the Pacific: The Life of Legendary Marine John Basilone, about a Marine who was awarded the Medal of Honor recipient for his actions at the Battle of Guadalcanal, was completed days before Brady's death.
Brady also wrote novels about the fashion and media worlds that provided an insider's insights, including Paris One, Designs and The Press Lord.
He was hired as publisher of Women's Wear Daily in 1964, recrafting the publication to reach out to both the clothing industry and the general public, and creating W, a fashion magazine aimed at the consumer spun off from WWD. He was named as editor and publisher of Harper's Bazaar in 1971, where his efforts to aim the publication at a younger audience led to his early termination. His experiences in fashion publishing provided input for his 1974 book Superchic about the industry, described in a review in The Washington Post as "his revenge on the fashion world, a way to settle scores with two former employers".
Clay Felker, publisher of New York magazine, hired Brady to create its Intelligencer column. Rupert Murdoch hired Brady in 1974 to serve as editor of his new weekly tabloid Star, a magazine specializing in celebrity gossip and scandals. Murdoch shifted Brady to the New York Post after he bought the paper in 1976, where Brady was a major participant in the creation of Page Six, a celebrity news and gossip column, giving the column its name and serving as the column's first editor.
Brady added to his workload with an Advertising Age column that was started in 1977 and another column included in Crain's New York Business when that publication was created in 1984.
He wrote the In Step With celebrity profile column in Parade starting in 1986 and continuing until his death. His final column, a profile of actor Kevin Bacon, appeared in the February 15, 2009 issue.
He received the W.Y. Boyd Literary Award for Excellence in Military Fiction from the American Library Association in 2003 for his novel Warning of War.
Brady died at age 80 on January 26, 2009 at his home in Manhattan. A cause of death was not immediately disclosed, but Brady had suffered a stroke several years before his death. He was survived by his wife (the former Florence Kelly, whom he married in 1958), two daughters (including author Susan Konig), four grandchildren and brother Monsignor Tom Brady who died March 28, 2013.James Brady, Paris One Dell (fiction); (1978)
James Brady, Why Marines Fight St. Martin's Griffin; Reprint edition (2008)
James Brady, The Marine: A Novel of War from Guadalcanal to Korea St. Martin's Griffin (2004)
James Brady, The Marines of Autumn: A Novel of the Korean War St. Martin's Griffin; Reprint edition (2001)
James Brady, The Coldest War: A Memoir of Korea St. Martin's Griffin (1990)
James Brady, Warning of War: A Novel of the North China Marines St. Martin's Griffin (2003)
James Brady, The Scariest Place in the World: A Marine Returns to North Korea St. Martin's Griffin (2006)
James Brady, A Hamptons Christmas St. Martin's Paperbacks (2001)
James Brady, Gin Lane St. Martin's Press (1998)
Brady, James (2010). Hero of the Pacific: The Life of Marine Legend John Basilone. Wiley. ISBN 978-0-470-37941-7.