Born in Pennsylvania, June 29, 1862, he graduated from West Point in 1888. He was an honor graduate of the Army School of the Line, 1910; and also graduated from the Army Staff College, 1911, Army War College, 1913.
He was commissioned a Second Lieutenant of Infantry on June 11, 1888 and promoted through the ranks to Brigadier General, National Army, August 5, 1917; Major General, N.A., April 16, 1918; Brigadier General, U.S. Army, November 8, 1918; Major General, U.S. Army, May 5, 1921.
He was in the Sioux Indian Campaign, 1890-91; the Battle of El Caney, Cuba, July 1, 1898; and the investment of Santiago until its surrender on July 16, 1898; duty in the Philippines during the Insurrection there, 1899-1902; with a regiment in Alaska, 1905-06; a Member of the General Staff Corps, 1916-17; served in France in World War I, June 26, 1917-June 8, 1919; Chief of Staff, American Expeditionary Forces, May 6, 1918-May 26, 1919; Commandant, General Staff College, Washington, D.C.
He died as a Major General in Washington, D.C. on April 30, 1922 and was buried in Section 3 of Arlington National Cemetery.
His wife, Elizabeth McAndrew (Died: December 21, 1946), is buried with him.
His brother, Patrick H. McAndrew, Colonel, United States Army, is also buried in Arlington National Cemetery. His nephew, Thomas Richard McAndrew, Major, United States Army, is also buried in Arlington National Cemetery.