He fought at the Battle of Bremule in 1119, where his father defeated King LOUIS VI of France (RIN 1531). In 1122 he was created Earl of Gloucester. In 1123, he led a force to assist in the capture of the castle of Brionne, which was held by rebel Norman barons. In 1126 he had custody of the imprisoned rebel, Robert, Duke of Normandy. In 1127 he did homage to the EMPRESS MATILDA, recognizng her as his father's successor to the throne.

When Stephen was chosen as king over the EMPRESS MATILDA, Robert did homage to him for his English lands. In 1137 he accompanied King Stephen to Normandy where a quarrel ensued. He then threw his support to MATILDA, who was in Normandy, and obtained the surrender of Caen and Bayeux to her husband, GEOFFREY PLANTAGANET, Count of Anjou (RIN 787). In Sep. 1139 he
he landed in England with MATILDA and took her to Arundel Castle. He became her commander-in-chief in the civil war which followed.

Robert was captured by Stephen's forces, but Stephen had also been previously captured by MATILDA's. The two were returned to their respective camps in an even exchange. MATILDA sent Robert to Anjou to attempt to convince her husband, GEOFFREY, to come to her aid. GEOFFREY declined to help until he had conquered Normandy, so Robert joined in his campaign. However, hearing that MATILDA was beseiged at Oxford, he hurried back to her assistance. He took MATILDA's and GEOFFREY's son, HENRY (the future King HENRY II) with him. In 1143 Robert defeated Stephen at Wilton and in 1144 he blockaded Malmesbury, Stephen refusing battle. MATILDA's support had gradually dwindled, so Robert was unable to continue to press her cause. In 1147 Robert sent HENRY back to Anjou. Later that year Robert died of fever at Bristol.