Why is there no info on Piergenon in the Phb? Does anyone have any resources on him?

Is that a deity? What world/campaign is he/she from?

If you mean Piergeiron Paladinson, the head Lord of Waterdeep, he is a human Paladin of Tyr, level 15

Oops, meant the FR campaign setting book.

15? wiener!

Piergeiron is mentioned in the Waterdeep section of the FRCS. All that's there is essentially what Skedaddle posted though; there was no picture with stats like with Drizzt or Halaster.

Is he in any of the novels, then?

There were some mentions of him in the Songs & Swords series, but again, not as a main character, far from it.