George Sangster was born around 1829 in Scotland. He married a woman named Isabella, and they had at least three children: Margaret, born around 1852; Isabella, born around 1854; and Ellen, born around 1856. They immigrated to America around 1854, settling in Brooklyn, New York. By 1855, Sangster was working as a laborer. He apparently joined Brooklyn’s Dutch Reformed Church on October 3, 1857. His wife probably died in the mid-1850s, and he married Margaret Elizabeth Munson in the Dutch Reformed Church on October 12, 1858. Their son George was born around 1859.
His wife was a writer who published the book Little Janney in 1855. By 1860, Sangster was working as a stove maker, and he owned $2,000 of personal property. Sangster enlisted in the Union army on May 27, 1862, and mustered in as a lieutenant colonel in the 47th New York State Militia. He mustered out on September 1, 1862, when his 3-month term of enlistment expired. He may have reenlisted the following year and mustered in as a lieutenant colonel in the 47th New York Infantry on June 17, 1863. He mustered out again on July 23, 1863. He settled in Norfolk, Virginia, after he war and earned a living as a merchant. The family probably returned to Brooklyn soon afterward, and he died there in 1871.