Felix was a bishop from Burgundy who arrived in England around 630. According to Bede, he came at the invitation of King Sigeberht of East Anglia, who had been baptized during his years of exile in Gaul and wanted a bishop to complete the conversion of his kingdom.

Archbishop Honorius of Canterbury sent Felix to East Anglia, where he established his episcopal seat at Dunwich — then a significant coastal town, now largely lost to the sea. From there, Felix conducted a systematic mission that Bede describes as entirely successful: he 'freed all that province from its long wickedness and unhappiness, bringing it to the faith and the works of righteousness and to the gift of everlasting happiness.'

Felix founded a school modeled on the schools of Kent (themselves modeled on Frankish and Italian precedents) where East Anglian boys could be trained for the priesthood. He also worked alongside the Irish monk Fursey, who established a monastery at Burgh Castle — a collaboration between Roman and Celtic traditions characteristic of the period.

Felix served as bishop for seventeen years and died around 647 or 648. His body was later translated to Soham and eventually to Ramsey Abbey. The loss of Dunwich to the sea over subsequent centuries means that virtually nothing survives of his physical legacy, but his significance in the conversion of eastern England is well established.

Bede provides almost no miracle tradition for Felix, describing his work in straightforwardly historical terms. Later medieval sources — particularly the 12th-century Liber Eliensis — developed Felix's hagiography, but these are distant from the events and were produced in contexts that served the interests of the Ely monastic community.

The loss of Dunwich to coastal erosion from the medieval period onward has meant that physical traces of Felix's legacy have disappeared, though underwater archaeology has located elements of the medieval town. The town of Felixstowe preserves his name.