George W. Hamilton was born around 1841 in Cecil County, Maryland, to Hugh and Sarah Hamilton. His father was a weaver who owned $200 of real estate by 1850. He grew up and attended school in Cecil County, and by 1860, he was working as a laborer and coach maker.
He enlisted in the Union army on August 20, 1862, alongside his brother Hiram. He mustered in as a private in Company G of the 6th Maryland Infantry. According to his service records, he was 5 feet, 11 inches tall, with light hair and blue eyes. He fell ill in the fall of 1862, and he spent several months in a hospital in Frederick, Maryland. He eventually recovered and rejoined the regiment. He remained devoted to the Union cause, celebrating the “Flag which has so triumphantly waved over our peacefull and happy country for so long a period.” He vowed to “fight untill this Rebelion is crushed and that the Stars and Stripes shall again wave over every State in the union and when Rebels will be ashamed to confess thier traitorism.” He supported Black enlistment, explaining in July 1863 that "I do not think the government wrong for bringing the blacks into the field to fight it is better to do that than to let this rebelion run on for years." He died of typhoid fever in Washington, D.C., on August 22, 1863.