The son of John Sergeant, a schoolmaster at Cheltenham School, and his wife Mary Anne, daughter of George Lewis, he was born at Barrow-on-Humber, Lincolnshire, on 10 November 1841.
[1] After education under a private tutor, Sergeant matriculated at St Catharine's College, Cambridge, in 1861, graduating B.A.
On leaving college, he spent a period as assistant master under Henry Hayman at Cheltenham grammar school.
There followed Greece in the Nineteenth Century: a Record of Hellenic Emancipation and Progress, 1821–1897, with illustrations, in 1897.
[1] Sergeant married on 12 April 1871 Emma Louisa, daughter of James Robertson of Cheltenham.