He was born at Maryton, by Montrose, in Angus, Scotland, the son of James Cargill and his wife, Helen Thomson.
[1] Cargill briefly worked in Glasgow at the offices of the East India merchants William Milne & Co for whom, in 1844, he set sail for Ceylon to establish a branch of the company there.
In 1861 Cargill returned to Glasgow to acquire the whole business which carried on an extensive trade with India as well as Ceylon.
Four years later he bought it outright and invested further funds but it was up against the monopoly of the Kingdom of Upper Burma which controlled oil exploration.
It was in 1886 that Cargill obtained exploration rights, as well as improving refining methods in Rangoon, and he founded Burmah Oil Ltd that year.