Of unknown origin, the mormaers are attested for the first time in a document perhaps dating to 1115.

The first known mormaer, Malise I, is mentioned by Ailred of Rievaulx as leading native Scots in the company of King David at the Battle of the Standard, 1138.

The last ruler of the Strathearn line was Malise, also Earl of Caithness and Orkney, who had his earldom forfeited by King Edward Balliol.

In 1344 it was regranted by King David to Maurice de Moravia, a royal favourite who had a vague claim to the earldom as Malise's nephew and also stepfather.

In 1631, William Graham, 7th Earl of Menteith was confirmed in this dignity as heir of line of Euphemia Stewart, Countess of Strathearn (died 1415), but was forced to settle for the less prestigious title of the Earl of Airth in 1633.