He was elected prior of Llanthony Priory in the middle 1120s, and was named bishop by King Henry I of England in 1130.

[4] He was a schoolmaster in England, teaching elementary subjects,[3] before he went to study theology under William of Champeaux and Anselm of Laon.

Bethune was often appointed a judge delegate by the papacy to try cases and disputes, which had been referred back to England by the popes.

[12] The historian David Knowles said of Bethune that he was a man of wide outlook, with a great desire for reform.

[4] During this time, Bethune assisted Theobald of Bec, the new Archbishop of Canterbury, in consecrating Maurice as Bishop of Bangor.

Bethune had earlier persuaded the bishop-elect to swear fealty to King Stephen, after Maurice had originally refused.

Bethune's standing as a bishop known for his piety and independence of the king helped persuade Maurice that the homage was canonical.

[15] Welsh raids at the beginning of Stephen's reign had driven Bethune's former canons from Llanthony and the bishop gave them refuge at Hereford before establishing them at a new site near Gloucester.

Bethune was forced to travel to Pisa to secure an order from Innocent II declaring that the chapter obey their bishop.

[22] King Stephen gave permission for some of England's bishops, including Bethune, to attend the Council of Reims in 1148.

Theobald of Bec was expressly forbidden to attend, but he managed to evade those watching him and arrived in Reims along with his clerk, Thomas Becket.

A medieval catalogue of works at Llanthony Priory also recorded that they owned a collection of letters by Bethune, but this has not survived.

[29] Although the life describes miracles that took place at Bethune's tomb, no evidence survives of a formal cult being developed, and he was never canonised.