Ethelbald, the eldest surviving son of King Ethelwulf and his first wife, Osburh, was born around 831-834. He would reign for only a short time, from 856-860.

Ethelbald's father, King Ethelwulf, embarked on a lengthy pilgrimage to Rome, taking with him his youngest and favourite son, Alfred, whom he hoped to name as his heir. During the King's absence, Wessex had been governed by a council of ministers under the joint leadership of Ethelbald, St. Swithin, Bishop of Winchester and Bishop Ealstan of Sherborne. In a pre-emptive move Ethelbald was crowned King of Wessex at Kingston-upon-Thames before his father's return.

Ethelbald was the very antithesis of his pious and mild-mannered father, he was a tough and hardened warrior like Egbert. Many were sorry that the ageing Ethelwulf, never an inspiring figure, had returned at all, much preferring the rule of his warlike son. Ethelwulf prevented the looming prospect of civil war by his acceptance of the situation and abdication.

After the death of his father two years later, Ethelbald foolishly made himself highly unpopular with the church by scandalously marrying his sixteen year old stepmother, Judith of France. The relationship was deemed incestuous and in direct contravention of church law. Her outraged father, Charles the Bald, King of France, intervened and forced his errant daughter into a nunnery. The much married Judith later eloped with Baldwin, Count of Flanders, making her the ancestress of another Queen of England, Matilda of Flanders, the consort of England's first Norman King, William the Conqueror.

Despite the scandal with his stepmother, Ethelbald made a popular king. He died at Sherbourne in Dorset on 20 December, 860, aged around 35, after a four year reign. He seems to have been greatly mourned by his people, although Bishop Asser describes him as being "headstrong and arbitrary" It should be remembered, however, that he evoked the censure of the church through his uncanonical marriage, making Asser's opinion of the King a highly biased one.