A native of San Antonio, Texas, Nathman graduated with distinction from the United States Naval Academy in 1970.

Nathman has served in a variety of sea, shore and joint assignments, and flown over 40 different types of aircraft during his career.

Nathman subsequently served as Director, Air Warfare, on the Chief of Naval Operations staff in Washington, D.C.

On 6 September 2012, Nathman spoke at the 2012 Democratic National Convention.In July 2022, he joined with other former U.S. military leaders in condemning former president and commander in chief, Donald Trump.

"While rioters tried to thwart the peaceful transfer of power and ransacked the Capitol on Jan. 6, 2021, the president and commander in chief, Donald Trump, abdicated his duty to preserve, protect and defend the Constitution.