Sidney John Barton was born in 1886 in Southampton, Hampshire, England and his birth was registered in the first quarter of that year. He was the son of Alfred Barton (b. 1859) and Ada Emily Barnes (b. 1862), both Southampton-natives who had married in 1882.

Sidney and his family don't seem to appear on the 1891 census. On the 1901 census Alfred and his family are resident at 32 Threefield Lane, St Mary, Southampton and his father is described as a dock labourer. His listed siblings were: Alice Kate (b. 1883), Norah Emmeline (b. 1888), Alfred Alexander (b. 1890), Harry Richard (b. 1893), Olive Lydia (b. 1895), Grace Elizabeth (b. 1897) and Maurice Frederick (b. 1900). Another child, Ruby Alexandra would be born in 1906.

On the 1911 census Sidney is still unmarried and living at home with his parents at 85 College Street, Southampton and he is described as a messenger's clerk.

When Sidney signed-on to the Titanic, on 4 April 1912, he gave his address as 85 College Street, Southampton. As a third class steward he received monthly wages of £3 15s. His last ship had been the Olympic.

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

Sidney Barton is mentioned on a gravestone in the Old Cemetery, Southampton Common, Southampton.

His parents continued to live in Southampton. His father passed away in 1924 and his mother in 1930.