The sources did not indicate why Hegseth asked George to leave his post.
The move was first reported by CBS News on Thursday.
George, an infantry officer who served in Iraq and Afghanistan, was confirmed to the top Army post in 2023. Terms in that role usually run for four years.
Prior to holding the top job, George was the vice chief of the Army and, before that, the senior military adviser to then-defence secretary Lloyd Austin.
George's removal adds to recent upheaval at all levels of leadership at the Pentagon, including the firing in 2025 of the previous chairman of the Joint Chiefs of Staff, Air Force General CQ Brown, as well as the chief of naval operations and Air Force vice-chief of staff.
Hegseth, a former Fox News host, has moved quickly to reshape the department, firing top generals and admirals as he seeks to implement Trump's national security agenda.
The office for George did not immediately respond to a request for comment.
