Public services often extend beyond the public sector, requiring collaboration and interaction between public and private actors. Initiating digital service innovations in collaboration is challenging, especially in large-scale public service ecosystems. While individual service providers may have clashing interests, balancing incremental improvements and radical changes (i.e., pursuing ambidextrous development) requires collective efforts. We report a case of a digital service ecosystem related to the bureaucracy of a person’s death in Finland. We focused on the pursuit of collective ambidexterity, which requires collaborative development among various actors. The suggested contributions are summarized as four propositions to facilitate collective ambidexterity in service ecosystems: 1) adoption of multiple collaboration modes pursuing both efficiency gains and innovation outcomes, 2) parallel foci of top-down and bottom-up ambidextrous balancing, 3) governance of collaboration and (dis)benefits management both intra- and inter-organizationally, and 4) focus on citizen life-events to facilitate development across organizational silos and innovation beyond sub-optimization.