Mr Johnston takes over from current financial officer Richard Goodman, who will step-down from the position at the end of this month.
Mr Goodman will remain at the company as executive vice president responsible for business information systems, global procurement, global operations and post-merger integration.
Mr Johnston has been at PepsiCo for twenty three years and currently serves as executive vice president of PepsiCo Global Operations. He has also been senior vice president of mergers and acquisitions and chief financial officer for PepsiCo Beverages & Foods.
Indra Nooyi, chairman and CEO of PepsiCo, said: "Richard and I have been working closely on an orderly succession plan, given his desire to step-down from his current position at age 62, and we agreed that the recent completion of our two major bottling acquisitions makes this an opportune time for the transition."
