Walter was born in Birmingham in about 1896, the son of Joseph Caswell. By 1911, he was living with his brother, John James, and his family, at 35 Hart Road, Wednesfield, Wolverhampton. Walter was a labourer for the weldless tube works.
Walter enlisted in the 2nd Battalion of the South Staffordshire Regiment (number 23832), but was killed in action on 17 February 1917. He is buried at Adanac Military Cemetery in Miraumont, France, and is remembered on the Wednesfield roll of honour.