Along with his brother, Chief Rabbi Aaron Hart, he was one of the founders of the Ashkenazic Jewish community in England.

During the high-treasurership of Lord Godolphin in the reign of Queen Anne, a government appointment was conferred upon Hart, and thereby he attained to great affluence.

In 1722, motivated by religious zeal and by the fact that the London Jewish community had outgrown its temporary house of prayer, Hart contributed a large sum to cover the cost of erecting a permanent building.

[1] In the same year he was recognised as a resident of Great Britain, after he received letters of denization.

[2] Hart married Prudence Heilbuth with who he had six children, among them Judith Levy, the philanthropist.