Defense Secretary Lloyd Austin's chief of staff is stepping down, the Pentagon announced Wednesday, five months after Austin and his top aide faced blowback for not telling the White House that he was in the hospital for treatment of prostate cancer.

       Officials told reporters that Kelly Magsamen's resignation had nothing to do with the hospitalization scandal in January, which remains under review by the Defense Department inspector general.

       A separate internal review led by Austin's office concluded there was no indication of "ill intent or an attempt to obfuscate" the situation and did not assign blame, essentially clearing Magsamen, who upon learning of Austin's medical condition was home sick with the flu.

       MORE: TIMELINE: When key figures found out about Lloyd Austin's hospitalization

       In a lengthy statement, Austin said Magsamen remained an example of "exemplary public service."

       "From day one of this administration, Kelly's leadership, counsel, and selfless service made our nation safer, made the lives of our people better and more rewarding, and rendered the heavy burden of this office of mine a good bit lighter," he wrote. "At every stage, she provided a steady hand guiding our staff and the Department. I am -- and will remain -- in her debt."

       Kelly Magsamen serves as the Chief of Staff to Secretary of Defense Lloyd J. Austin, III.

       Chad J. Mcneeley/DoD

       Austin was diagnosed with prostate cancer late last year and initially used personal leave to undergo what the Pentagon later said was a minimally invasive procedure. But subsequent complications from that procedure resulted in a second hospitalization on New Year's Day. The White House didn't learn about either event until Jan. 4, a day before he was released.

       Austin has since apologized for keeping his health quiet from the White House, Congress and the public. As President Joe Biden's top civilian military adviser, Austin oversees U.S. military policy commands U.S. forces at Biden's behest.

       MORE: Defense Secretary Lloyd Austin says cancer diagnosis was 'gut punch,' instinct was keep private

       Austin also insists that at each point when he was unable to perform his duties -- including during surgery -- that his deputy was officially in charge and had full access to communications with the White House -- even if the White House didn't know it.

       Defense Secretary Lloyd J. Austin testifies during the House Armed Services Committee hear...Show more ---Show more

       Tom Williams/CQ-Roll Call, Inc via Getty Images

       "We did not handle this right. And I did not handle this right," he told the House Armed Services Committee in February. "And as you know, I have apologized … including directly to the president. And I take full responsibility."

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       Republican critics have questioned the validity of Austin's internal review which said staff concerns about medical privacy and a rapidly changing situation were mostly to blame. The public summary did not, however, answer key questions about when individual members of his staff became aware of his condition and whether the defense secretary himself was advised to alert the White House but chose not to.

       An independent investigation by the Pentagon's inspector general has not been released, and officials said they cannot say when it might be made public.