She was the only child and heir of Earl Alexander, and succeeded to the earldom de jure upon his death in 1402.
She became a ward of her grandfather Robert Stewart, 1st Duke of Albany from a precept of 11 July 1405,[1] and never seems to have exercised much power in the province of Ross.
Governor Albany became Regent and persuaded her to resign the earldom to his own second son, John Stewart, Earl of Buchan.
[2] This action was challenged by Domhnall of Islay, Lord of the Isles, who claimed the earldom on behalf of his wife Mariota and who became an enemy of the Albany Stewarts.
In 1411 he marched an army of 10,000 Islesmen and Ross vassals against Albany's main northern ally, Alexander Stewart, Earl of Mar.