Ehrensvärd was born on 16 September 1858 at Tosterup Castle, Tomelilla Municipality, Sweden, the son of County Governor Albert Ehrensvärd and his wife Ingeborg Hedvig Vogt (from Norway). He had fours siblings; Albert Ehrensvärd (1867–1940), Henriette Eleonore Ingeborg Ehrensvärd (born 1853), Anna Louise Dorotée (born 1855) and Augustine Sofia Amalia (1862–1944).
