Henry Clay Garrison was born on July 10, 1835, in New Jersey to Edmund F. Garrison and Rebecca Dare. His father was a merchant who owned $15,000 of real estate by 1850. The family lived in Gloucester County, New Jersey, and Garrison attended school there before working as a clerk. He married Mary Elizabeth Kirkpatrick in Swedesboro, New Jersey, on April 26, 1860, and they had at least two children: Adelaide, born around 1863; and Gertrude, born around 1869. Garrison enlisted in the Union army on October 21, 1861, and mustered in as a private in Company F of the 7th New Jersey Infantry later that day. He was promoted to corporal on August 1, 1862. The regiment took part in the Battles of Williamsburg, Fredericksburg, Chancellorsville, Gettysburg, and Spotsylvania Court House and the Siege of Petersburg. He mustered out on October 21, 1864, and returned to New Jersey. By 1870, Garrison was working as a constable, and he owned $2,600 of real estate and $1,000 of personal property. By 1900, he was working as a detective. He died in Swedesboro, New Jersey, on March 1, 1913.