Cohn, 60, who was president of Goldman Sachs from 2006 to 2016, also served a tumultuous tenure as President Donald Trump's assistant for economic policy in 2017-18.
“Cohn will work in partnership with [IBM Chief Executive Arvind] Krishna and the IBM Executive Leadership Team on a wide range of business initiatives and external engagement, in areas including business development, client services, public advocacy and client relationship management,” the Armonk, N.Y., tech giant said in a statement.
"Gary is a globally respected leader with deep experience operating at the center of business and government," Krishna said.
"As a senior representative of IBM, his knowledge of technology and business transformation, combined with policymaking expertise, will bring unique value to our clients and stakeholders, as we accelerate our hybrid cloud and AI strategy."
Cohn invests in the cybersecurity, blockchain infrastructure, regulatory technology and medical technology sectors, IBM said. He also serves on the boards of several technology companies.
IBM shares recently traded at $125.37, up 1.2%. Eleven months ago IBM shares were trading above $158. They have dropped 22% over the past 10 years.
Morningstar analyst Julie Bhusal Sharma puts fair value for the company at $125.
“While IBM has tried to refresh its diverse offerings, we think IBM’s moat is deteriorating, as the cloud transition chips away at IBM’s competitive advantage associated with customer switching costs,” she wrote in a November commentary.