Fa'side Castle was built in the early twelfth century by Robert De Quency who came from Normandy with William the Conqueror. The site was chosen because its location afforded excellent defence. After 1189 various charters were granted to the de Quency's by the Cisterian Abbey of Newbattle. The grants provided land for grazing, cutting peat and the first charter granting the right to extract coal in East Lothian. The De Quency interest continued until 1306. Ela De Quency and her husband forfeited the estate to Robert I of Scotland because of their support of Edward I of England. Subsequently, Robert I's nephew, Sir Alexander Seaton, obtained a grant for the lands of Tranent including Fawside and Longniddry. In 1371, William de Seton gave Wester Fausyde to John of Fausyde marking the beginning of the Fawside interest in the estate until the seventeenth century. The Fawsides experienced relative harmony with their tenants and neighbours except for occasional territorial skirmishes between the Fawsidians and their Prestonian neighbours.
On the 9th September 1547 the inhabitants of Fawside Castle witnessed the Battle of Little Fawside. This was a preliminary skirmish between the Scots and the English cavalry and after initial success the Scots were finally routed at a loss of 1300 men. The following day the Battle of Pinkie was fought. This conflict was between Somerset, Protector of England and the Earl of Arran, Regent of Scotland. For many hours Fawside Castle was the centre of the battle which saw Lady Fawside and the occupants of the little castel or pile ... on Fauxsyde Bray shoot English soldiers with their limited supply of handguns and hakbutes. They were eventually overcome and burned with the building.
Although Fa'side Castle was not completely destroyed the family of Fawside moved to a more modern mansion evidenced at the nearby house with the inscription I.F. & I.L. 1618. This probably refers to James Fawside and his wife Janet Lawson who were the last Fawsides to preside over the estate. Thereafter came a long line of owners in 1631 an Edinburgh merchant named Hamilton; in 1647 the First Earl of Queensferry; in 1704 Dundas of Arniston. From then until 1968 the property was uninhabited only avoiding demolition through the efforts of the Fawside Preservation Committee set up by Nigel Tranter through the St. Andrews Society of East Lothian. Restoration of the property began in 1976 with the new owners Mr. and Mrs. Tom Craig. In 1988 James and Charmie Douglas bought the property but sold it a year later to Ian Brash, an architect who is the current owner.