Quote Originally Posted by JaySee
He's considered a traitor to Konoha. He wasn't one of the 4th's teachers. The 3rd and Jiraiya were his teachers, but I guess he was an elder to be called sensei. Orochimaru picked up Kabuto after he left. Orochimaru left before the 4th became the 4th.
Orochimaru was pissed that he didn't get chosen as the 4th. So, I think it would've been just after.