Born in a slum in Whitechapel, London, he joined his brother Harry in Cape Colony in 1873 during the "diamond rush" which accompanied the discovery of diamonds at Kimberley. His brother had gone out in 1871 and had been working as a comedian and conjurer under the name Harry Barnato. Consequently Issacs changed his name to Barney Barnato.
He formed the Barnato Diamond Mining Company and within ten years he had become a millionaire, primarily by buying worked_out diamond mines area and mining the abandoned blue earth heaps.
He competed with Cecil Rhodes in taking over the diamond mining industry in Cape Colony by aggressive buying out of competitors, although in the end Rhodes succeeded in buying him and his brother out for around four million pounds — a collosal sum in the late 1880s. Barnato subsequently became Kimberley's member of parliament in the Cape Parliament from 1889 until his death.
He committed suicide by jumping into the ocean and drowning from a ship taking him to England in 1897. His body was recovered and buried in Willesden cemetery, near London.
BarneyBarnato's eagerness to work hard and his good instinct about money was of great value to South Africa and specially to Johannesburg in particular, during a time of gigantic economic growth and development.
BarneyBarnato se werkywer en geldelik vernuf het tot voordeel gestrek van Suid-Afrika oor die algemeen en Johannesburg in die besonder in 'n tyd van ontsaglike ekonomiese ontwikkeling.
In 1874 Barney and his brother commenced business as diamond-dealers under the firm-name of "Barnato Brothers"; and in 1876 Barney, who was then worth about $15,000, purchased four claims in the Kimberley mine, which soon brought in an income of $9,000 a week.
Barnato was returned for the Legislative Assembly of Cape Colony as member for Kimberley, after a fierce contest, in 1888, and was reelected in 1894, although he had been burned in effigy a short time before.
In November, 1895, the lord mayor of London gave a banquet in honor of Barnato, who, wishing to be under no obligation, handed a check for $50,000 to him as a donation to the fund for the benefit of the poor in Spitalfields, in whose welfare the lord mayor was then actively interested.