Thomas H. Mason was born around 1808 in England. He eventually immigrated to America and settled in New York. He got married, and he had at least ten children, including: Ann, born on March 4, 1828; Alice, born around 1833; Thomas, born around 1836; Eliza, born around 1843; Harriet, born around 1845; James, born around 1847; Henry, born around 1849; Isabel, born around 1851; and Samuel, born around 1853. He lived in Fallsburg, New York, and worked as a tailor. By 1850, he owned $350 of real estate. A decade later, he owned $100 of real estate and $50 of personal property. His wife died in the late 1850s.
He enlisted in the Union army on August 17, 1861, and he mustered in as a sergeant in Company I of the 56th New York Infantry on September 3. He apparently lied about his age, claiming that he was 44 years old. The regiment took part in the Peninsula campaign and the Seven Days Battles. He was discharged for disability on September 16, 1862, and he died sometime afterward.