O’Mahony became chairman and CEO for Asia-Pacific and Australia in 2004, a role that later expanded to include EMEA and Latin America, and prompted him to relocate from Sydney to New York.
Last year, he took on responsibility for CRIB and Asia after Saatchis forged an alliance with Fallon and named Simon Francis EMEA CEO. O’Mahony is reportedly set to take up a new role at Saatchis’ outfit Inspiros.