Younger son of James and Katherine. He is recorded in the Scots Society's register of Apprentices "Alexander, son to James Lidderdale of the Isles, apprentice with John Johnstone, of Newbie, Merchant, 4.4.1592." On March 9, 1596, he was admitted a Freeman and Burgess of Kirkcudbright with power "to use the haill liberteis and fredomes thairoff quha hes become to be leill & trew to the toun" etc.

He engaged in trade, for on March 25, 1601, the Kirkcudbright Town Council Records (P.390) under an entry "Townschip" has "The quhilk day Alexander Lidderdale Merchand and Robert Allane Skippar of one bark of Leithe callit the 'Blissing' entered the same bark laidint with Hectopoist wyne (Heotopois or Hectopoist a Haultpoyis, a town near Bordeaux) extending to xxxiij twnis (Tuns) wyne."

Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.