He was the eldest son of Alexander Pennecuik of Newhall, Edinburgh, who had been a surgeon under Johan Banér in the Thirty Years' War, and afterwards in the Scottish army of the First English Civil War in England.
[1] Pennecuik was in practice as a physician in Tweeddale, and on good terms with a number of Scottish men of letters.
In 1702 his elder daughter married, and Pennecuik gave with her the estate of Newhall.
[1] Pennecuik published poetical pieces:[1] At the request of Sir Robert Sibbald, who was writing about the counties of Scotland, Pennecuik wrote a description of Tweeddale with his friend the advocate John Forbes of Newhall; it appeared as A Geographical, Historical Description of the Shire of Tweeddale, with a Miscellany and curious Collection of Select Scottish Poems (1715).
[1] He has been confused with another Alexander Pennecuik (died 1730), said to be his nephew, a writer of verse.