"I wanted to stay in the job," McChrystal told NBC's "Today." "But I wanted to do what was best for the mission."
McChrystal was the head of U.S. forces in Afghanistan 2010 when Rolling Stone magazine published an article in which he said the Obama administration hadn't committed enough troops to the embattled country. The story also quoted anonymous members of McChrystal's staff criticizing Vice President Biden and other White House officials over the war.
McChrystal apologized, but the ensuing media flare-up provoked the general to resign shortly after.
In his memoir, My Share of the Task, set for release on Monday, McChrystal accepts responsibility for the comments, and said the decision to step down was his alone.
"Regardless of how I judged the story for fairness or accuracy, responsibility was mine," the memoir says, according to reports.
"I called no one for advice," he continued.
In accepting McChrystal's resignation, Obama praised his "extraordinary dedication" to the country, but said the incident revealed conduct that "does not meet the standard that should be set by a commanding general."
"It undermines the civilian control of the military that is at the core of our Democratic system," Obama said at the time, "and it erodes the trust that's necessary for our team to work together to achieve our objectives in Afghanistan."
McChrystal was replaced by Gen. David Petraeus, who resigned as head of the CIA in November when news broke of his extramarital affair with his biographer.