Christopher Smart was born in Shipbourne in Kent, England on the Fairlawne estate of William, Viscount Vane, younger son of Lord Barnard of Barnard Castle. He was, according to his nephew, "of a delicate constitution having been born earlier than the natural period". He was baptised in Wrotham parish on 11 May 1722. Smart's father was Peter Smart, steward or bailiff of Fairlawne. His mother, Winifred (née Griffiths) was from Radnorshire, Wales. Before giving birth to Christopher, Winifred had two daughters, Margaret and Mary Anne.