Deasy will work alongside Taylor Wright, the co-head of global capital markets, the British bank said.
Deasy left Credit Suisse a few weeks ago, just months after being promoted to regional co-head of its investment banking & capital markets (IBCM) unit.
JF Astier and John Miller, who currently lead the business, are in "active dialogue" with the bank about their roles, a Barclays' spokesperson said.
Astier and Miller were promoted in 2021 to lead the investment banking business as part of a new management team.
(Reporting by Baranjot Kaur in Bengaluru and Lawrence White; Editing by Sriraj Kalluvila)