The Magpies completed the loan signing of Kenedy for the 2018-2019 season.
The Brazilian managed two goals in 13 appearances for Newcastle in the second half of last season.
Now fans will be hoping he can improve even more in the coming season, lifting the club higher up the Premier League table in the process.
Benitez said to the club's official website: "I'm really pleased to have Kenedy back with us. I'm sure every fan will be happy with this signing.
"Hopefully he can keep playing at the same level that he reached with us last season. I wish him all the best for his time here."
Kenedy added: "I am so happy with this interest from Rafa Benitez, that he came back for me. I want to keep it going, the work that I did here before, for the new season.
"I have received many, many messages on social media from the fans. They made me feel appreciated, so I wanted to come here in this new season and give everything on the pitch."