Charles Maurice Maxim was born on August 17, 1842, in New Castle, Pennsylvania, to Marcus Maxim and Rebecca Officer. His father was a “master farmer” who owned $1,500 of real estate and $400 of personal property in 1860. The family moved to Rochester, Massachusetts, in the 1840s, and Maxim attended school there before beginning work as a farm laborer.
He enlisted in the Union army on October 25, 1861, and mustered in as a private in Company E of the 23rd Massachusetts Infantry on December 4. According to his service records, he was 5 feet, 8¾ inches tall, with dark hair and blue eyes. The men were stationed in North Carolina until 1864, when the army transferred them to Virginia. They took part in the Battle of Cold Harbor and the siege of Petersburg. He was promoted to sergeant on December 2, 1863, and to 1st lieutenant on October 14, 1864. He mustered out on June 25, 1865.
Maxim returned to Rochester after the war and resumed his work as a farm laborer. He married Charity A. Bishop there on November 1, 1871. Their daughter Annie was born around 1873. They lived in Rochester, and Maxim earned a living as a farmer. His wife died in October 1915. He remained in Rochester for the rest of his life, living with his daughter and her husband. He died in Rochester on April 12, 1933.