On 14 January 1586 he was engaged to marry Christian Marjoribanks, the daughter of Simon Marjoribanks a burgess of the City of Edinburgh and a local merchant; the couple would have two sons, who died in their youth. To mark the marriage, and the end of his apprenticeship, Heriot was given 1500 merks by his father to establish his own business, which he did in a small "luckenbooth" near St. Giles' Cathedral, on the site of the entrance of the modern Signet Library.