Ælfgar (died c. 1060) was the son of Leofric, Earl of Mercia, by his famous mother Godgifu (Lady Godiva). He succeeded to his father's title and responsibilities on the latter's death in 1057. He gained the additional title of Earl of East Anglia, but also was exiled for a time. Through the first marriage of his daughter he would become father-in-law of the Welsh king Gruffydd ap Llywelyn; a few years after his death, his daughter would become a widow and marry English King Harold.
Ælfgar profited from the exile of Earl Godwin of Wessex and his sons in 1051. He was given the Earldom of East Anglia, which had been that of Harold, son of Godwin. Earl Godwin and King Edward were reconciled the following year, so Harold was restored to his earldom—but not for long. At Easter 1053 Godwin died, so Harold became Earl of Wessex, and the earldom of East Anglia returned to Ælfgar.
Ælfgar seems to have learned from the tactics Godwin used to put pressure on King Edward. When he was himself exiled in 1055, he raised a fleet of 18 ships in Ireland and then turned to Wales, where King Gruffydd agreed to join forces with him against King Edward. Two miles from Hereford, on 24 October, they clashed with the army of the Earl of Herefordshire, Ralph the Timid. The Earl and his men eventually took flight, and Gruffydd and Ælfgar pursued them, killing and wounding as they went, and enacting savage reprisals on Hereford. They despoiled and burnt the town, killing many of its citizens. King Edward ordered an army mustered and put Earl Harold in charge of it. This was more formidable opposition, and Ælfgar and Gruffydd fled to South Wales. However the issue was resolved by diplomacy and Earl Ælfgar was reinstated.
Ælfgar is known to have had at least four children. One son, Burgheard, predeceased his father, expiring while returning from Rome early in 1060 and was buried at Reims. This led Ælfgar to give to Reims Abbey lands in Staffordshire and Shropshire, which became the endowment for Lapley Priory. He was survived by three children, two sons, Edwin, later Earl of Mercia, and Morcar, later Earl of Northumbria, and a daughter Ealdgyth, who was first married to Welsh king Gruffydd ap Llywelyn and later to Harold Godwinson, King of England.