Traditional media such as television are increasingly adopting interaction logic as a way to engage viewers. In this paper, we report on the design of a smartphone application that facilitates the participatory production process of #TheDay, a two-minute item in an infotainment TV show, which is broadcasted twice a week on national television. #TheDay leverages a co-creation approach as it allows viewers to submit and discuss self-produced video content, this way empowering them to share their take on topics imposed by TV producers. We report on #TheDay’s eight-month deployment. Through a mixed methods approach, we learn how the TV producers succeeded in triggering viewer interaction, also on a long-term. From our findings, we distill three considerations for the design of interactive applications that support professional producers in deploying participatory forms of media production with sustained user commitment.