Son of Sir William Cunningham of Caprington (d. 1740) and Janet Dick (d. 1753), daughter of Sir James Dick of Prestonfield. Married firstly to Janet Dick (d. 1760), a niece of his mother's. Married secondly (1762) to Mary Butler. In all, he had more than 10 children.
Baptized as Alexander Cunningham, when his older brother, Sir William Dick, died without issue in 1746, he succeeded to the estate and name of his mother, and the baronetcy of his brother, and it was as Alexander Dick that he became widely known as a much-respected physician and benefactor
He completed his medical studies under Dr Boerhaave in Leyden in August 1725. Little more than a year later he received another diploma as Doctor of Medicine from the University of St. Andrews. On November 7, 1727, he was admitted Fellow of the Royal College of Physicians of Edinburgh, of which in 1756 he was unanimously elected president.
According to Significant Scots
"his death [in 1785], notwithstanding the very advanced age he had reached, was generally lamented as a loss to society. He was of a kind and amiable character, and remarkable for the mildness and sweetness of his disposition, and for the unwearied zeal and activity with which he promoted the advancement of medical knowledge in Scotland, as well as the improvement and welfare of his native city."1
Boswell visited Sir Alexander at his estate at Prestonfield together with John Boswell and a Dr Livingston on February 7, 1767.1
On August 17, 1773, during Dr Johnson's stay in Edinburgh before he and Boswell set out on their tour of Scotland, they had Sir Alexander for dinner together with Sir David Dalrymple, John Maclaurin, Dr James Gregory and John Boswell. (James) Boswell wrote of Dick in his Journal of a Tour to the Hebrides that "his amiable character and ingenious and cultivated mind are so generally known (he was then on the verge of seventy, and is now – 1785 – eighty-one, with his faculties entire, his heart warm, and his temper gay)."
- 1See journal entry for that day in Boswell in Search of a Wife.