 Gilbert married Catherine Maxwell, daughter of Herbert Maxwell, 1st Lord Maxwell.He married, secondly, Isabel Ogilvy, daughter of Sir Walter Ogilvy of Lintrathen and Isabel Glen, after 1460.Kennedy, created 1st Lord of Kennedy between 27 March 1457 and 20 March 1458, in addition held the office of Keeper of the Castle of Lochdoun and the office of Constable of Stirling Castle, bestowed upon him in 1466.