Clementina was the youngest of the ten daughters of John Walkinshaw of Barrowhill (1671–1731) and his wife Katherine Paterson (c. 1683–1780). The Walkinshaws owned the lands of Barrowfield and Camlachie, and her father had become a wealthy Glasgow merchant (founding the textile village of Calton). However, he was also an Episcopalian and a Jacobite who had fought for the Prince's father in the rising of 1715, been captured at the Battle of Sheriffmuir, before escaping from Stirling Castle and fleeing to Europe. In 1717, he had been pardoned by the British Government and returned to Glasgow, where his youngest daughter was born probably at Camlachie. However, Clementina was largely educated on the Continent, and later converted to Roman Catholicism. In 1746, she was living at the home of her uncle Sir Hugh Paterson at Bannockburn, near Stirling. The Prince came to Sir Hugh's home in early January 1746 where he first met Clementina, and he returned later that month to be nursed by her from what appears to have been a cold. Given that she was living under her uncle's protection, it is not thought the two were lovers at this time.