By the mid-13th century, the lands of Plenderleith were held by Nicholas de Prendrelathe, lay abbott of Jedburgh Abbey.

Upon the Bruce's accession to the throne of Scotland in 1306 as Robert I, he erected the lands of Plenderleith, then held by Sir John's son, William, into a barony, apparently in recognition of this service.

In 1346, Edward Balliol, who had usurped the title "King of Scots" with the support of Edward III of England, declared Plenderleith forfeit to the crown as a result of Sir George's support for the Scottish king David II's invasion of England.

In 1755, his successor, John Ker, 3rd Duke and Earl of Roxburghe, received a Crown Charter from George II confirming to him the barony of Plenderleith.

The current and 31st Baron of Plenderleith is Clifford Harmon of Dallas, Texas, who succeeded to the barony in 2007 following the death of his father.