Ange Postecoglou's former assistant at Yokohama F.Marinos, Papas has signed on for the next two seasons, returning to Australia after spending much of the past few years in various roles overseas.
Newcastle are in the hands of a consortium of fellow A-League club owners after former owner Martin Lee was stripped of the A-League and W-League licence in January.
Papas said he felt supported to make signings -- and make the most of existing talent -- to build a squad and a club-wide "identity" that would hold them in good stead in the future.
"The owners that are in charge now really want to invest in the club, in terms of making it more successful," Papas told reporters on Monday. "It's had a couple of difficult years obviously, as well.
"That's the kind of challenge that I want for myself, that's the kind of challenge that I relish, so I'm looking forward to it.
"... Definitely the objective is to improve and that's the reason for coming on board.
"I believe I've got the capabilities and we'll be able to build a squad that gives us the opportunity to improve.
"But it's step-by-step right now."
Papas said he was in "robust discussions" with several foreign strikers to replace departed marksman Roy O'Donovan.
Papas, 41, spent two-and-a-half years working under Postecoglou at Yokohama F.Marinos and said the former Socceroos boss had taught him to have belief in himself and the style of play he wants to implement.
"Ange always makes time as well and just wished [me] all the best," he said. "He's got his own massive challenge [at Celtic] not only for himself but for Australian football as well.
"All I can say is that [he's] a great support.
"I had an opportunity to work in the best league in Asia with him as well, winning the league there, obviously playing in the Asian Champions League as well.
"He's really set a blueprint for Australian coaches in general about you can be ambitious, you can always think above -- you don't have to just settle, as a lot of people think we should settle.
"I completely agree [with Postecoglou] on that.
"So I don't want to really want to place a limit on what we can do at Newcastle, I just want to get on the ground and start running."