Born 25 October 1856 at South Petherton, Somerset, the eldest of ten children (seven sons) of Samuel Augustus Sylvester, who had retired from his sheep station in Australia in 1855, and Mary Catherine, his wife, daughter of the Rev Joseph Holden Johnson, Vicar of Tilshead, Devizes. He was educated at Weston-super-Mare and received the early part of his medical education from Samuel Grose, FRCS, at Melksham, Wilts, before he proceeded to St Bartholomew's Hospital. He became surgeon, AMS, 31 July 1880, surgeon-major and major, RAMC, 31 July 1892, lieutenant-colonel 1900, and was granted local rank of colonel whilst acting as PMO of a General Hospital in South Africa, 12 February 1901. He retired on 19 October 1907, and was re-employed during the war from 1 February 1915. He was on the Livery of the Grocers' Company, and was then a freeman of the City of London. He died unmarried at Bournemouth on 23 March 1934, and his ashes were buried at Tonbridge.