His eldest son and heir apparent, Oliver St John, was in 1641 summoned to the House of Lords through a writ of acceleration in his father's junior title of Baron St John of Bletsoe.
However, he predeceased his father (killed at the Battle of Edgehill in 1642); nevertheless, the writ of acceleration means that he is formally known as the fifth Baron St John of Bletsoe.
The creation in the Jacobite Peerage occurred on 26 July 1715 when Henry St John, 1st Viscount Bolingbroke, was created Earl of Bolingbroke by the Old Pretender, this title not being recognised by the British Government, although Bolingbroke returned from exile, was pardoned, and briefly returned to royal favour.
He died on 12 December 1751, aged 73, his second wife having predeceased him by one year, and the Jacobite earldom became extinct.
Bolingbroke's great-nephew Frederick St John, succeeded him in the viscountcy.