George Millen mustered into the 7th NJ Volunteers on April 14, 1864 on a 3 year enlistment. He was promoted to 1st Sergeant of Co. K on Sept. 6, 1864, and then promoted to 2nd Lieutenant on March 28, 1865. He survived the war, being mustered out at its end on July 17th, 1865.
While there is no surviving evidence to say what he did after the war was over, we know that he married a woman named Jeanette Arnold, and lived in New Jersey until the age of 77. He passed away on June 15, 1921, and is buried with his wife in Hilltop Cemetery in Mendham, NJ.