John Clement Callender was born at St Mark's Surbiton on the 24th of March, 1896, the son of Clement Boncher Callender, a gentleman, and Lucy Agnes Callender of 26 Maple Road, Surbiton. He was christened at St Mark's Church Surbiton on the 5th of May 1896.

He was educated at Shrewsbury House where he received Honours in 1906. He then moved on to his senior school, Magdalen College, Oxford. Here he was a chorister and clearly made a great impression during his time at the school - as one of the six houses is named after him. He was also a member of Kingston Rowing Club, along with Francis Wrentmore Brown.

He was commissioned as a 2nd Lieutenant in the 3/4th Battalion Oxfordshire and Buckinghamshire Light Infantry and was later posted to the 2/4th Battalion of his regiment.

He was killed in France on the 21st of August, 1917 - aged 21. He is commemorated on the Tyne Cot Memorial Panel 96 to 98 and the Shrewsbury House War Memorial.