Cohn said in a tweet Tuesday that he was “honored to be joining IBM,” which he described as “one the world’s most important companies, providing technology that helps organizations be agile and resilient in unpredictable times.”Once viewed as a potential successor to Lloyd Blankfein as CEO of Wall Street giant Goldman Sachs (GS), Cohn joined the White House shortly after Trump took over in 2017. But his tenure there as the director of the National Economic Council was rocky, and he left the administration in 2018 following a disagreement with Trump about the decision to impose more tariffs on steel and aluminum imports. Cohn also publicly rebuked Trump in 2017 after the President refused to criticize white supremacists after a rally in Charlottesville, Virginia. Cohn said at the time that Trump’s response caused him “distress.” In an interview with CNN in 2019, Cohn also said that he was “concerned” there was no one left in the White House to stand up to Trump and “tell him what he doesn’t want to hear.”Read MoreFor IBM, the hiring of Cohn brings the company a top executive who is familiar with the inner workings of Wall Street and Washington — if not necessarily the world of high tech.Marc Benioff of Salesforce is the CNN Business CEO of 2020But the company said in a press release that Cohn will help CEO Arvind Krishna with a “wide range of business initiatives and external engagement, in areas including business development, client services, public advocacy and client relationship management.””Gary is a globally respected leader with deep experience operating at the center of business and government,” Krishna said in the press release. “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,” Krishna added.That could mean more strategic acquisitions or partnerships. IBM has made a big bet on cloud computing in the past few years, most notably with its $34 billion purchase of software giant Red Hat in 2019. Despite that deal, IBM’s stock has lagged behind the broader market — as well as cloud rivals Microsoft (MSFT), Google owner Alphabet (GOOGL), Amazon (AMZN) and Salesforce (CRM) — over the past few years.Krishna took over as Big Blue CEO last April following the retirement of longtime IBM chief Ginni Rometty. Since then, IBM has announced plans to spin off its legacy technology infrastructure business to focus even more on the cloud. The spinoff is expected to occur by the end of 2021.