Chad was one of four brothers all of whom became Northumbrian missionary clergy — Cedd (Essex), Cynibil, Caelin, and Chad. Like Cuthbert he was educated at Lindisfarne under Aidan, and later spent time in Ireland with the Irish monks. He was made abbot of Lastingham in 664 after his brother Cedd's death.
In 666 the king of Northumbria appointed him bishop of York during Wilfrid's prolonged absence in Gaul; when Wilfrid returned, Theodore of Tarsus, the new Archbishop of Canterbury, ruled the appointment irregular and asked Chad to step down. Chad answered with humility: 'If you know that I have not received the office of bishop rightly, I will gladly step aside.' Theodore was so moved that he had him reconsecrated and assigned to the new diocese of Mercia, which Chad established at Lichfield in 669.
He governed Mercia for only three years, but he laid the foundations of the great central English see. He traveled on foot rather than horseback for humility; Theodore reportedly lifted him bodily into a saddle when his journeys grew too long. He died of plague in 672 after a brief illness, in his small cell beside the church at Lichfield.
Three healing wells at Stowe and Lichfield are dedicated to him; pilgrims to his shrine were so numerous that medieval Lichfield Cathedral was rebuilt in the 13th century specifically to accommodate them.