Frank Mertens discovered his interest in stage performance while taking part in a stand-up comedy workshop. In 2003 he presented his first comedy show, which was followed by performances at
various venues in Bremen.
During this time his passion for acting grew, prompting him to enrol in a drama course and various camera-acting workshops. This led to a series of roles in short films, a telemovie and a feature
prior to his work on Sleeping Dogs.