It's been about 19 months now. He debuted early 2002, just before Wrestlemania, and in time for the brand extension, although he hadn't wrestled at that point.
Actually, he debuted the night after WM X-8, killing poos Spike
Dudley with the Triple Powerbomb during a hardcore match. Oddly enough, he didn't even try to win the hardcore belt, even though he killed everybody involved in the match as well