In August 1547, Clinton was sent to Scotland with a fleet of twelve ships to support the Siege of St Andrews Castle and prevent a French intervention, but he arrived too late.
He captured Broughty Castle on 24 September, refortified it with the aid of an Italian military engineer, and installed Andrew Dudley as its captain, leaving him three ships, the Mary Hamborough, the Barque Eger, and the Phoenix.
[6] Clinton commanded the English fleet during the invasion of Scotland by Edward Seymour and provided naval artillery support at the Battle of Pinkie on 15 September 1547.
He received instructions to take a fleet to Scotland in May 1548, land troops in Fife to devastate the coastal towns and, if possible, accept the surrender of Perth from the Master of Ruthven.
Upon his return to England, Clinton took command of the English fleet, raided the French coast and in 1558 burnt the town of Le Conquet and the surrounding area.
Thomas Smith described his reception in Paris, and a visit to the Tuileries Palace where Charles IX of France showed him gardens designed by Catherine de' Medici.