He was converted to Christianity by Finan of Lindisfarne, in about 653, and in the same year married Alhflede, a daughter of Oswiu of Northumbria. Sometime during the next two years, Oswiu defeated and killed Penda at the Battle of Winwaed, which gave Oswiu the kingship of Mercia, and afterwards Peada is king in Middle Anglia, although it is unclear whether he was appointed before, by Penda, or after, by Oswiu.
In any case, Peada only had enough time to help found the monastery at Peterborough before he was murdered on Easter of 656.