Sir John Parnell, 2nd Baronet

Sir John's great-grandson, the legendary land-reformer Charles Stewart Parnell

The only son of Sir John Parnell, 1st Baronet, Parnell was the great-grandfather of Charles Stewart Parnell, known as the uncrowned king of Ireland and was best known for opposing (with his son Henry)[3] the Act of Union between the two kingdoms of Great Britain and Ireland in 1801. Before this, Parnell was a Commander of Irish Volunteers[5] and had been instrumental in winning the right for Irish Roman Catholics to vote and to be elected to Parliament.[3] However, the latter faltered when the parliament of Ireland was dissolved in 1800.

Henry Grattan described Parnell as "an honest, straightforward, independent man, possessed of considerable ability and much public spirit; as Chancellor of the Exchequer he was not deficient, and he served his country by his plan to reduce the interest of money. He was amiable in private, mild in disposition, but firm in mind and purpose. His conduct at the Union did him honour, and proved how warmly he was attached to the interests of his country, and on this account he was dismissed".

Parnell married Laetitia Charlotte Brooke in 1774,[6] and together they had four children. Their eldest son John Augustus was a deaf mute who was housed in a large walled garden for most of his life, while their second son Henry Brooke Parnell would go on to inherit the baronetcy and follow his own political career, becoming an Irish peer and also a member of parliament for Queen's County in the House of Commons at Westminster.[3]

Sir John Parnell, 2nd Baronet, left another son William, who in turn had a son, John Henry Parnell. The fourth son of John Henry Parnell is Charles Stewart Parnell.[7]