The little that is known about Saint Cedd comes to us mainly from the writing of Saint Bede in his Ecclesiastical History Of The English People. The following account is based entirely on Book 3 of Bede's History.

Cedd was born in the kingdom of Northumbria and brought up on the island of Lindisfarne by Saint Aidan. He was one of four brothers: Chad (originally Ceadda), Cynibil and Caelin being his siblings. The first datable reference to Cedd by Bede makes clear that he was a priest by the year 653. This probably pushes his birth date back to the early 620s. It is likely that Cedd was oldest of the brothers and was acknowledged the head of the family. While he was alive, he seems to have taken the lead, while Chad was his chosen successor.

Aidan had come to Northumbria from Iona, bringing with him a set of practices that are known as the Celtic Rite. As well as superficial differences over the Computus (calculation of the date of Easter), and the cut of the tonsure, these involved a pattern of Church organization fundamentally different from the diocesan structure that was evolving on the continent of Europe. Activity centred on monasteries, which acted as bases for peripatetic missionary bishops. There was a strong emphasis on personal asceticism, on Biblical exegesis, and on eschatology. Aidan was well-known for his personal austerity and disregard for the trappings of wealth and power, and Bede several times stresses that Cedd and Chad absorbed his example and traditions. Bede tells us that Chad and many other Northumbrians went to study with the Irish after the death of Aidan (651). Cedd is not mentioned as one of these wandering scholars. He is further pictured by Bede as very close to Aidan's successor, Finan. So is highly likely that he owed his entire formation as a priest and scholar to Aidan and to Lindisfarne.