Robert de Ferrers, 1st Earl of Derby, was born about 1062 in Normandy, France, a younger son of Henri de Ferrers and his wife Berta. When he was a small child, his father accompanied William the Conqueror during his invasion of England. The family was rewarded with a grant of Tutbury Castle in Staffordshire and 114 manors in Derbyshire.

Robert's elder brothers Egenulph and William died during their father's lifetime, leaving him the only surviving son and heir to the family estates.

As a young man, Robert led the men of Derbyshire in King Stephen of England's victory over King David I of Scotland at the Battle of the Standard at Northallerton. For his service, the king created him Earl of Derby.

Robert died in 1139, and was succeeded by his second but eldest surviving son Robert de Ferrers, 2nd Earl of Derby.