The 21-year-old spent the second half of last season on loan at St. James’ Park, and admitted that the Toon Army had found a special place in his heart during that stint.
"It wasn’t straightforward at all,” Willock told BBC Radio Newcastle.
“It was a big step for me in my career to leave my boyhood club and move away from my comfort zone.
"The Newcastle fans, team and manager made it easier to make the decision.
"The love I have for Newcastle is immense, so it made the decision very easy for me towards the end.”
Willock continued: "I had the option to stay (at Arsenal) or look at other avenues to better my career and I choose the second option.
"Coming back to Newcastle was always at the top of my list.
“When I decided to leave Arsenal, there was only one place I was going to go and it was going to be Newcastle.”
He added: “For me, it was all about the feeling I got when I played in front of the fans and the feeling when I stepped out at St James’s Park.
"The love I have for the club never left me when I went back to Arsenal.
"It was always in the back of my mind and heart that something was missing and I feel like it was Newcastle United.”
We’ve gathered the best of today’s Premier League transfer speculation below…
1. Molumby set for loan exit
Brighton & Hove Albion have been tipped to send midfielder Jayson Molumby out on loan for another season. The Republic of Ireland international spent time with Preston last season, and Millwall the campaign before that. (The Sun) (Photo by Stu Forster/Getty Images)
Photo: Stu Forster
2. Gunners optimistic over Odegaard
Arsenal are hopeful of signing Martin Odegaard on a £30m deal from Real Madrid, and to have him ready to face Chelsea in the Premier League this weekend. He impressed on loan with the Gunners last season. (Sky Sports) (Photo by Fran Santiago/Getty Images)
Photo: Fran Santiago
3. Palace bid for Hughes
Crystal Palace are understood to have had a £5m bid knocked back for Watford midfielder Will Hughes. It has been suggested that the Eagles board won't up their offer, despite manager Patrick Vieira being keen to get the playmaker on board. (Daily Mail) (Photo by Richard Heathcote/Getty Images)
Photo: Richard Heathcote
4. Blues still keen on Kounde
Chelsea have been tipped to make a final attempt to sign Sevilla defender Jules Kounde, following the £34m sale of Tammy Abraham to Roma. It is suggested that the boost to their finances could help fund a big-money move for the France international. (Sport Witness) (Photo by Fran Santiago/Getty Images)
Photo: Fran Santiago