Crowley will take over a position that has been vacant since Gavin O'Reilly replaced his father Sir Anthony O'Reilly as chief executive of the group.
The promotion of Gavin O'Reilly prompted changes at board level, which included Crowley and Ivan Fallon, chief executive of INM in the UK, stepping down from the board.
Crowley's latest role will not have board-level responsibilities.
He will be replaced by Joe Webb, currently managing director of the group's Irish operations, which include the Belfast Telegraph.
Separately, about two-thirds of shareholders (65.74%) voted against rebel shareholder's Denis O'Brien's bid to revoke the board's authority to issue new shares as part of its restructuring plan.
IN&M chairman Brian Hillary, said: "IN&M welcomes shareholders' decisive support at today's extraordinary general meeting. IN&M remains resolute in its focus to restore the group to a secure and stable financial position in line with its consensual restructuring programme."
Earlier this week, bondholders gave the green light to a proposal that involved the company issuing more than 720 million shares.
Shareholder meetings will be held at the end of the month regarding the board's proposal to sell off its outdoor advertising business and its proposed rights issue.