Garret Sproul was born around 1832 in New Jersey to James and Julia Sproul. His father was a carpenter and farmer who owned $7,000 of real estate and $1,200 of personal property by 1860. He grew up and attended school in Raritan, New Jersey, and by 1850, he was working as a carpenter. He married Christiana Taylor sometime in the 1850s, and they had at least three children: William, born around 1858; Flora, born around 1860; and Lillian, born around 1872. They settled in Jersey City, New Jersey, and by 1860, Sproul owned $200 of personal property. His wife died around 1909, and by 1910, he was living in Burlington, New Jersey. He died in 1915.