Sydney George Hiscock was born in Southampton, Hampshire, England in the second half of 1887 and his birth was registered in the September quarter of that year. He was the son of James Edward Hiscock (1853-1892) and Sarah Ann Sharp (b. 1859), both Southampton-natives who had been married in Southampton in 1878.

Sydney first appears on the 1891 census with his family. By then they are living at 21 West Front, St Mary, Southampton. His father is described as a painter and sign writer. Also listed are his siblings: James John (b. 1881) and three-day old Elizabeth Ellen.

Sydney's father died in 1892. By the time of the 1901 census Sydney is listed as a boarder (minus the rest of his family) at the Seaman's Orphanage, 17 Beechwood Road, Southampton. His mother and surviving siblings do not appear on the census. His mother was remarried around 1909 (as per the 1911 census) to Harry Saunders (b. 1855 in Scotland). Sydney, his mother, sister and stepfather (a shipwright) appear on the 1911 census living at 38 Chantry Road, Southampton. Sydney is described as a steward for the White Star Line.

When he signed-on to the Titanic, on 4 April 1912, he gave his address as 38 Chantry Road, Southampton. His last ship had been the Olympic. As a plates steward he received monthly wages of £3 15s.

Hiscock died in the sinking. His body, if recovered, was never identified.

He is remembered on his mother's headstone in Old Common Cemetery, Southampton (section D181, plot 118).