Hayden swapped the Emirates for St. James' Park this summer.
The 21-year-old defender, who can also play in midfield, departed the Emirates Stadium having made just two first-team appearances under Wenger, both of which came in the early rounds of the Capital One Cup.
Countless Arsenal youth prospects have fallen by the wayside at the club only to go on to success after leaving, and Wenger admitted that he wanted to give Hayden an opportunity which would prevent his career stagnating at such an early age.
Wenger told Arsenal Player: "He couldn't get the chance here and I decided to let him go and have an opportunity. At 21 years of age, you need to play or you stand still - and if you stand still you waste your career.
"He’s very intelligent and very good physically as well, he has good strength. I remember some games he played, like at West Brom in the League Cup where he did extremely well, and I gave him a chance to go up to Hull.
"It went quite well, they liked him and they wanted to buy him as well. I think Newcastle is a good opportunity for him."
Hayden has already shown signs that he can be an important member of Rafael Benitez's squad at Newcastle this season, impressing during pre-season friendlies.
His Arsenal education and Championship experience with Hull stand him in good stead to fight for a regular place in Benitez's side either in the centre of defence or, as seems more likely, in a defensive midfield role.