John Cena joined wwe in the year 2001 . the date is unknown . if you want to read avout him go to this site http://prowrestling.wikia.com/wiki/John_Cena . if you want to read wikia of any other superstar from wwe , tna, ucw , ecw etc. go to http://prowrestling.wikia.com.
He hasn't actually left.
He Joined on the 27th of June, 2002
John Cena appeared on the Smackdown brand when he joined WWE in the spring of 2002. My Source: My memory.
john cena did get rehired
the Miz Defended the WWE Title
John Cena,MVP,Drew Brees, and more WWE superstars
yes John Cena will win the wwe championship at wrestlemania 29
yes.
yes john cena does have a girlfriend.
john cena will return in 2011
in 2009 edge beat john cena and became wwe heavyweight champion
On the WWE Homepage it says that John Cena was champion before Edge was