The U.S. Senate on Tuesday confirmed the nomination of Eric Fanning, who is gay, to serve as secretary of the Army.
Mr. Fanning, who was nominated to the post by President Obama in March, is the first openly gay person to head any branch of the U.S. military.
His nomination had been blocked until now by Kansas Sen. Pat Roberts, a Republican, over concern about Mr. Fanning's policy toward Guantanamo Bay.
Mr. Roberts removed the hold on the vote Tuesday, saying he had received assurances from the administration in private that detainees at the detention camp would not be moved to Fort Leavenworth, Kansas.
Gay rights groups celebrated Mr. Fanning's appointment.
"Eric Fanning's historic confirmation today as Secretary of the U.S. Army is a demonstration of the continued progress towards fairness and equality in our nation's armed forces," Human Rights Campaign Chad Griffin said in a statement.
Mr. Fanning's appointment comes five years after the repeal of Don't Ask, Don't Tell. Prior to his appointment, Mr. Fanning served as a congressional staffer and a consultant before joining the Department of Defense, where he held both Army and Air Force positions.