Campbell itself derives from the Gaelic, "Caimbeul", or Wry mouth (cam beul). In the 11th Century, Archibald (Gillespie) Campbell acquired the Lordship of Loch Awe through marriage with Eva, the daughter of Paul O'Duin or Paul Insporran (the latter was the King of Scots' treasurer). Through this Eva, the Campbells are descended from the ancient hero, Dairmid Duibhne, boar hunter of Kintyre.

The rise of this clan can be traced to the 6th Campbell of Lochawe, Colin, who was knighted by King Alexander III in 1280. From the beginning, the Campbells upheld the royal writ in the West - a consistent policy that put them on a collision course with the MacDonald Lords of the Isles. One of the Campbell chiefs married the sister of Robert the Bruce. Only during the Protestant Reformation of 1560, and their adoption of the Protestant religion, did this loyalty to the king waver. In this struggle, 2 successive Earls of Argyll were executed by the King.

Ultimately, though, the Campbells triumphed with the Glorious Revolution of 1688. By 1701, when the Earl of Argyll was made 1st Duke of Argyll by William III, the Campbells were the pre-eminent clan of the Western Highlands.

The original Campbell stronghold was on the island of Innischonaill on the freshwater Loch Awe. In 1474, it moved to Inveraray on the seawater of Loch Fyne, from which the Clan Campbell expanded throughout Argyll.

In all their involvement with national politics, the Campbell Lairds never forgot that they were Chiefs of a clan. They always secured legal titles to the lands they won, and they backed this up with strength of arms where need be. Their methods varied, but were effective: acquiring forfeited MacDonald territories in Kintyre; carrying off heiresses by force in order to marry them to their own sons; and purchase of other chiefs' debts and mortgages and then foreclosing on them. Only when they came up against a power equal to their own, that of the Earls or Dukes of Atholl to the east, was their expansion to the east brought up short.

There was no shortage of physical courage with these Campbells. The First Colonel of the Scots Guards was Archibald, the 9th Earl of Argyll (executed by James II in 1685). The Cawdor Campbell branch alone have won 3 Victoria Crosses. The 2nd Duke of Argyll was one of the first two Field Marshals ever appointed in the British Army.