The 39-year-old, who led Donegal to the All-Ireland title this year, will be based at Lennoxtown and will help in the progression of Celtic's young players.
"It's a fantastic opportunity for me on an individual level and I'm very thankful to Neil Lennon for giving me this chance and bringing me into the club," said McGuinness.
"Obviously I work in amateur sport and the opportunity to work in professional sport in any capacity is a wonderful chance for me and one I'm very looking forward to."
Celtic boss Lennon has been impressed by the achievements of McGuinness during his time at Donegal, and believes the club have made a great appointment.
"We are delighted Jim has agreed to join us," he said. "He is a first-class coach and manager and a high-quality individual who has achieved so much already in sport.
"We feel he will add real value to the club in terms of moving our young players forward and in making sure they develop in the right way for the benefit of the club."
Lennon also revealed that Celtic's majority shareholder Dermot Desmond was behind McGuinness's appointment.
"Dermot made me aware of Jim's position and made the introduction," Lennon said.
"We had a long conversation about both sports and sport in general and there is stuff I can learn from him (Jim) and there is stuff he can learn from us so it is a win-win situation.
"Jim has a skill set that we don't have here, in terms of the psychological side of the game. It is a huge part of sport.
"He will player profile the younger players, look at their strengths and weaknesses, study their background and their state of mind.
"He will not be able to coach, he is not a qualified football coach but he does know sport and has excelled in his own sport.
"So the cross to football will not be a problem.
"He will predominantly work with younger players but if I feel there is a first-team player that would benefit from Jim's skill I would have no hesitation in using him.
"It will have no effect on what he is doing at Donegal.
"He will probably initially come in two days per week and we will take it from there."