Simplify the following text for a Grade 9 native English-speaking person.
Original: Layfield is best known by his ring names , Bradshaw , John `` Bradshaw '' Layfield or JBL while working for WWE , where he was the longest reigning WWE Champion in SmackDown history with a reign lasting 280 days .
Simplified: He is the longest reigning World Champion in SmackDown history longest reigning WWE Champion in SmackDown history which he held for 280 days .