General Stanley McChrystal, who was fired as the head of US and Nato forces in Afghanistan last week, has told the US army he is retiring.
Colonel Tom Collins, a spokesman for the army, said McChrystal notified the military of his intention to retire on Monday but had not submitted formal retirement papers yet.
Barack Obama, the US president, relieved McChrystal of his command last week after the general and his top aides appeared to be dismissive of Obama and his civilian advisers in a Rolling Stone magazine article.
In announcing his acceptance of McChrystal's resignation, Obama had said he did so with regret and praised the general's long army career.
But he said McChrystal's remarks in the magazine article were unbecoming of a commanding general and "undermines the civilian control of the military that is at the core of our democratic system".
McChrystal, who said it had been a "privilege and honour" to have served as the US and Nato commander in Afghanistan for a year, called his magazine comments "a mistake reflecting poor judgment".
He added that he strongly supported the president's strategy in Afghanistan, a strategy Obama made clear the change in command would not significantly alter.
Obama has nominated General David Petraeus, the head of US Central Command who had been supervising McChrystal, to take command of the war in Afghanistan.
The 55-year-old McChrystal has been a military officer for 34 years.