Jack, Vice President North Sea for M-I Swaco and a representative/director on several industry bodies and associations, is widely known and respected in the oil and gas sector.
AFC chairman Stewart Milne told RedWeb: "I indicated at the time of the appointment of Colin Welsh that, if we are to meet the major challenges that lie ahead and deliver against our stated objectives, achieve success on the park, build stronger relations with our fan base, deliver the new Stadium and Soccer Academy, and make an increasing contribution to the wider community, we require some new thinking, added energy and a new approach at Board level.
"We firmly believe that Ian with his wide experience, energy and enthusiasm, combined with his extensive oil and gas contacts, will add real strength to the board."
Ian Jack added: "In order for the club to be able to compete again at the top end of the table, it's vital to get the right product both on and off the pitch.
"We have an excellent management team who have made some good additions to the playing staff.
"Through my appointment and that of Colin Welsh last month, the chairman and the other members of the board have acknowledged that if this is going to be achieved and the transition to the best in class facilities at Loirston is to be a success, a new approach is required.
"To fully realise this ambition, the club will have to be more successful in fully engaging the supporters, sponsors and other investors and I am honoured to be invited to make a contribution".