The Arsenal defender has become Newcastle's fifth signing of the summer.
Hayden became Newcastle's fifth signing of the summer when he joined for an undisclosed fee from Arsenal on Monday, with the 21-year-old signing a five-year deal on Tyneside.
The England youth international spent last season on loan at Championship side Hull City, making 24 appearances and scoring once as he helped the Tigers win promotion back to the Premier League.
However, the young defender has chosen to remain in the second tier this season by joining Benitez's project at Newcastle, and he revealed that it was a conversation he had with the Spanish manager last month which convinced him that the move was the right one to make.
Hayden told the Magpies website that he was impressed with how much Benitez already knew about his game and the knowledgeable advice he received from the 56-year-old on how to improve.
The former Gunner said: "I met him in London in the middle of June and we had a good, two-hour long conversation. He explained a few things to me, what to improve and what I'm good at. It was good to know he's obviously been watching my games and things like that.
"For me, as soon as that meeting was done, I knew that this was the only place for me to come and [he was] the only manager I want to play under and learn from. It was brilliant. He was talking to me about tactical things, things that he'd learnt in the past - everything.
"So for me to have that initially was massive, and as soon as I left that meeting I knew that this was the right place for me to come. To meet him like that was fantastic and to work under him now is going to be even better and I think that the main thing I got from that meeting is I'm 100 per cent going to be a better player."
Hayden has become the second defensive signing by Benitez this summer, following the arrival of Jesus Gamez from Atletico Madrid last week.