In early times this name was spelt "Locard"or "Lokart". Like so many Scottish families, the Locards came from England where they were among those dispossessed of their lands by William the Conqueror. There were Lockards near Penrith in the twelfth century and later in Annandale, where the town of Lockerbie is said to be named after them. The family finally settled in Ayrshire and Lanarkshire, where they have held land for over seven hundred years.
The earliest paper in the family archives is a charter of 1323. Stephen Locard, grandfather of Sir Symon, founded the village of Stevenston in Ayrshire, which would have been a hamlet housing farmers and workers on his estate. His son, Symon, acquired lands in Lanarkshire and like his father, called a village which he founded, Symons Toun (today Symington) after himself. Symon, the second of Lee, won fame fighting alongside Robert the Bruce in the struggle to free Scotland from English domination, and was knighted for his loyal service. Sir Symon was among the knights, led by Sir James Douglas, who took Bruce's heart on Crusade in 1329 to atone for his murder of John Comyn in the Church of Greyfriars in 1306, and his consequent excommunication. Douglas carried the king's heart in a casket, of which Sir Symon carried the key. The crusade was ended prematurely when Douglas was killed fighting the Moors in Spain, but to commemorate the adventure and the honour done to the family, the family name was changed to Lockheart, later Lockhart. The heart within a fetterlock was from then on included in the arms of the family, and the deed commemorated in the motto. As well as a new name, the family gained a precious heirloom on the Crusade: the mysterious charm known as the Lee Penny. Sir Walter Scott used the story of its acquisition by the family as the basis for his novel, The Talisman. Sir Symon, captured a Moorish amir in battle in Spain, and received from the man's mother as part of his ransom, an amulet or stone with healing powers, which was later set in a silver coin, kept in a gold snuffbox which was a gift from Maria Theresa, Empress of Austria, to her general, Count James Lockhart.
Alan Lockhart of Lee was killed at the Battle of Pinkie in 1547. Sir James Lockhart of Lee was first knighted and later appointed to the Supreme Court bench, taking the title of "Lord Lee". A zealous royalist, he was eventually conveyed to the Tower of London. His son, Sir William eventually made his home in France. James Lockhart, who inherited the estates in 1777 held several titles from service on the Continent. The title of Count became extinct when James' only son, Charles, died without issue.
Lee Castle and estates have been out of the family hands for some time but the present chief, Angus Lockhart of Lee, still manages substantial lands around Carnwath.