A double intergenerational conundrum abounds in sustainability science as young generations of researchers have relatively little influence on current strategic decisions, but inherit their potential future consequences as professionals as well as human-beings. Collaborating with early career researchers (ECRs) in global sustainability initiatives can help address this conundrum. Guided by a model for how enhanced collaboration with ECRs can emerge, we assess the current state of integration of ECRs in five major global sustainability initiatives. Highlighting the increasingly organized state of ECR networks, we find that initiatives increasingly collaborate with ECRs and that some initiatives integrate them at strategic decision-making levels. Yet, current forms of collaboration are often institutionally fragile and can be strengthened in this respect.