Henry Northey Hooper was born around 1834 in Boston, Massachusetts, to Henry and Priscilla Hooper. His father was a copper dealer who owned $8,000 of real estate by 1850. He grew up and attended school in Boston, Massachusetts, and in 1858, he reportedly travelled to Paraguay to “take charge of the Great Bashenthal sheep range.” His passport application described him as 5 feet, 8 ½ inches tall, with light brown hair and dark blue eyes.
He returned to Massachusetts in the early 1860s. In May 1862, he received a commission as a 2nd lieutenant in Company E of the 32nd Massachusetts Infantry. He was promoted to 1st lieutenant in August 1862 and to captain in May 1863. The regiment took part in the Second Battle of Manassas, the Battle of Antietam, the Battle of Fredericksburg, and the Battle of Gettysburg. In September 1863, he was promoted to major in the 54th Massachusetts Infantry. He was promoted to lieutenant colonel in July 1864, and he mustered out on July 11, 1865.
He married Laura A. Kent on August 9, 1863, and they had at least seven children: Elenor, born around 1864; Henry, born around 1869; Laura, born around 1874; Harris, born around 1875; Kent, born around 1876; William, born around 1879; and James, born around 1882. After the war, he received a commission as a brigadier general in the Regular Army, and he served in Colorado. By 1870, he was working as a mining agent in the New Mexico Territory. He moved to Brookly, New York, in the 1870s, and he worked as an architect. He died in San Diego, California, on August 13, 1902.