She will be responsible for the day-to-day running of the shop and manage client and commercial relationships.
Reporting to Steven Moy, Isobar UK’s chief executive, Jones replaces Jon Boardman, who left the agency in November last year.
Jones joined Critical Mass in 2006 as a programme director. She then spent two years at 180 Amsterdam from 2008 before returning to Critical Mass. She took on her current role in 2014.
Moy said: "Susanne brings with her a breadth of expertise in transformative digital experiences, alongside a powerful skillset across operations, account management and production."