Alexander fought with Sir Andrew Murray, Guardian of the Realm, at the Battle of Culblean in the Scottish victory over the English force on 30 November 1335 and later at Boroughmuir, where Guy de Namur, a Flemish ally of England, was defeated and captured.
In June 1338 he smuggled supplies to Agnes Randolph, Countess of Dunbar allowing her to defend the castle against the siege by William Montagu, 1st Earl of Salisbury of England.
[4] Ramsay and his men recaptured Roxburgh Castle from the English at around dawn on 30 March 1342 by means of a night escalade.
In reward, King David II appointed Sir Alexander constable of Roxburgh and Sheriff of Teviotdale, which outraged Douglas.
Legend has it that he survived for seventeen days by eating small quantities of grain that fell through the cracks in the floor of the castle granary above the dungeon.