His father was Sir John Jacob, third baronet of Bromley, Middlesex (c1665–1740) and his mother was Dorothy (c1662–1749). Following his father, Hildebrand served in the army until at least 1715, then in 1717 he married Meriel, daughter of another baronet, Sir John Bland of Kippax-Park, Yorkshire.
His collected Works were published in 1735. Sir John served in the army from 1685 to 1702, seeing action at the Battle of Killiecrankie and in Ireland. He never succeeded to his father"s seat, dying in 1739, a year before Sir John.
The junior Sir Hildebrand was known as an excellent scholar, particularly of Hebrew.
He also wrote comedies: The Nest of (1738) comprised The Prodigal Reform"d, The Happy Constancy, and The Trial of Conjugal Love. The National Gallery in London has an engraving of him by Jacobus Houbraken after George Knapton (NPG D18752).
