Coming to London as a young man, he established a large business as an army contractor in Jermyn Street, trading as S. Isaac, Campbell & Company.
Their ships, outward bound with military stores and freighted home with cotton, were the most enterprising of blockade-runners between 1861 and 1865.
Isaac's eldest son Henry, who died at Nassau, West Indies, during the war, had much to do with this branch of the business.
Having raised a regiment of volunteers from among the workmen of his own factory at Northampton, Isaac was rewarded with the military rank of major.
[1] Queen Victoria accepted from Isaac a jewelled representation of the tunnel, in which the speck of light at the end of the excavation was represented by a brilliant.