I'm heading to ATL international airport to pick someone up...I want to meet him inside and...?

I have NEVER been to the airport before. I live in Alabama, and I'm driving there tonight to get him. He's going to be in the North Terminal, and arriving at midnight. I have a few questions. Will I have to go through security to get to baggage claim, and how much later should I arrive (after he lands) to not be waiting a long time?