Sidney was born in Aston in 1889, the son of William and Martha Gibbs. By 1911, he was serving in India with the military. At some point, he presumably moved to Wolverhampton, as his name is recorded on the Wolverhampton Roll of Honour.
Sidney originally enlisted as a Private with the Royal Welsh Fusiliers (service number 9798). He served from 11 August 1914. On 27 August 1917, he was transferred to the Labour Corps (service number 247860). Following sickness, he was discharged on 1 April 1919, and was awarded the Silver War Badge (number B259023) on 24 July 1919. He died in Wolverhampton in 1922.