The former Magpies manager, 66, left the club in 2009 after suffering a heart attack but has now returned to work alongside manager Alan Pardew.
Kinnear told Sky Sports News: "It's an interesting role for myself and I don't think I could be at a better club to do it."
Kinnear confirmed that he met with club owner Mike Ashley earlier on Sunday to sign a contract with the St James' Park outfit, with the agreement reportedly lasting three years.
"It's absolutely done," he said. "I signed it with Mike today and that's taken care of.
"I intend to meet Alan either tomorrow (Monday) or within the coming week to discuss the future and go through the team itself.
"We will discuss where it's glaringly clear we need to improve and that will be my job, to go and find those players."
When pressed during the Sky interview, Kinnear claims final transfer decisions will come down to him before back-pedalling somewhat and insisting he will not tread on any toes.
“It will be me [with the final say on transfers],” said Kinnear.
“Between the three of us we will discuss something and if Alan [Pardew, the manager] and Graham [Carr, the chief scout] decide against it, then my ears will be wide open.
“It is not a case of lump it or like it. Footballers come in all shape and sizes. If I feel we need to add some beef to the side, then I will do that.”
Kinnear's departure from the club four years ago was down to health issues but he insisted he is fit and ready to return to the Premier League.
The former Wimbledon and Nottingham Forest boss suffered a heart attack before a game against West Brom in February 2009 and, with United favourite Alan Shearer taking charge for the remainder of the season, Kinnear left the club at the end of his contract in May of that year.
But he said: "I'm as fit as a fiddle now. I'm absolutely delighted with the situation.
"I've been working out in the gym; I've lost lot of weight - I'm in the best physical shape I've ever been. I have turned down managerial jobs in the lower leagues, because I felt I'd gone past that and I wanted to get my teeth into something in the Premier League."
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