Miller attended the United States Merchant Marine Academy from 1967 to 1969, but left without receiving a degree.

Miller remained at this law firm until his appointment to the district court.

He was confirmed unanimously by the Senate on April 25, 2006, and received his commission the same day.

[1] In February 2019, Gray Miller ruled in National Coalition for Men v. Selective Service System that the male-only military draft in the United States is unconstitutional because it violates the equal protection clause of the Fourteenth Amendment to the US Constitution.

[5] However, the Court declined to consider it on the basis that the situation was under active review by Congress.