The Kennedy rise to power can be traced to their association with and support of the Bruce and the Earls of Carrick*, with whom a blood kinship was claimed. This relationship was cemented in 1372 when Robert II confirmed John Kennedy of Dunure as chief of his name and the bailie (magistrate) of Carrick. Gilbert Kennedy was named Lord Kennedy in the mid-1400s, and the Kennedys were given an upgraded title in 1509 when David Kennedy was created the Earl of Cassillis (pronounced Cassels) by James IV (unfortunately, both lost their lives at Flodden in 1513). Archibald Kennedy was created Baron Ailsa in 1806 by King William IV, which in turn changed to the Marquess of Ailsa in 1831. The titles Earl of Cassillis and Marquess of Ailsa are still in use.
*Earl of Carrick was a title associated with the Bruce and then bonded with his family when he became King of Scotland in 1306. In the 1400s it reverted to the crown and hence became the title of the heir to the throne. The current Earl of Carrick is Prince Charles.
- Gilbert Kennedy, 1st Lord Kennedy (1406-1480)
- John Kennedy, 2nd Lord Kennedy (died 1508)
- David Kennedy, 3rd Lord Kennedy (died 1513), was created 1st Earl of Cassillis in 1509
Earls of Cassillis
- David Kennedy, 1st Earl of Cassillis (1463-1513)
- Gilbert Kennedy, 2nd Earl of Cassillis (died 1527)
- Gilbert Kennedy, 3rd Earl of Cassillis (1515-1558)
- Gilbert Kennedy, 4th Earl of Cassillis (1541-1576)
- John Kennedy, 5th Earl of Cassillis (1573-1615)
- John Kennedy, 6th Earl of Cassillis (died 1668)
- John Kennedy, 7th Earl of Cassillis (1653-1701)
- John Kennedy, 8th Earl of Cassillis (1700-1759)
The title holder was in dispute from 1759 until 1762, when it was ruled in favor of Thomas Kennedy, who was the IV Baronet of Culzean.
- Thomas Kennedy, 9th Earl of Cassillis (died 1775)
- David Kennedy, 10th Earl of Cassillis (died 1792)
- Archibald Kennedy, 11th Earl of Cassillis (died 1794)
- Archibald Kennedy, 12th Earl of Cassillis (1770-1846), created Baron Ailsa in 1806
Marquesses of Ailsa
- Archibald Kennedy, 1st Marquess of Ailsa (1770-1846)
- Archibald Kennedy, 2nd Marquess of Ailsa (1816-1870)
- Archibald Kennedy, 3rd Marquess of Ailsa (1847-1938)
- Archibald Kennedy, 4th Marquess of Ailsa (1872-1943)
- Charles Kennedy, 5th Marquess of Ailsa (1875-1956)
- Angus Kennedy, 6th Marquess of Ailsa (1882-1957)
- Archibald David Kennedy, 7th Marquess of Ailsa (1924-1994)
- Archibald Angus Charles Kennedy, 8th Marquess of Ailsa (1956-2015)
- David Thomas Kennedy, 9th Marquess of Ailsa (born 1958)
The heir apparent to the title is the son of the 9th Marquess, Archibald David Kennedy, and he holds the title of Earl of Cassillis.