This marks the biggest film acquisition to date for the streaming service, reported Variety.
The comedy, directed by "Animal Kingdom" director David Michod is based on Michael Hastings' bestselling book "The Wild and Terrifying Inside Story of America's War in Afghanistan".
The film, will be produced by Pitt, 51, and his Plan B partners Dede Gardner and Jeremy Kleiner, along with Ian Bryce.
"We are so excited to be a part of the inspiring commitment by Netflix to produce cutting-edge content and to deliver it to a global audience," said the "Fight Club" star.
"War Machine" follows Pitt, a four-star US Military General, patterned after General Stanley McChrystal, determined to win the "impossible" war in Afghanistan.
The film will be available in theatres and to Netflix subscribers in 2016.
The streaming service made its first big splash at the Cannes Film Festival last month by acquiring worldwide distribution rights to the upcoming Kevin James comedy "The True Memoirs of an International Assassin".
