Older adults have long been considered critical actors in developing and implementing age-friendly community (AFC) initiatives. However, there has been limited empirical research on the ways they advance AFC implementation, especially in terms of their participation through AFC leadership roles (e.g. committee chairs, work group members). This study addresses this critical gap by exploring the functions that older adults exhibit in AFC implementation in the United States – namely, the underlying purposes and processes operating through their implementation actions. As one of the few studies exploring AFC implementation processes from the direct perspectives of older adults, this study conducted qualitative interviews with 23 older adult leaders of AFC initiatives across four states. Through reflexive thematic analysis, we identified two overarching thematic categories regarding the functions of their efforts towards AFC change. First, older adults advance AFC programme processes by guiding (e.g. determining priority areas) and carrying out (e.g. handling day-to-day programme logistics) the work. Second, older adults strengthen network capacity through connecting people and organizations to advance AFC implementation and spreading ageing-inclusive mindsets and practices among community actors. The findings support the view of older adults’ participation in AFC implementation as a multidimensional phenomenon wherein they employ multiple co-occurring functions that fluctuate dynamically across organizational roles, activities and tenure with the initiative. This study highlights the importance of continued research on the people enacting age-friendly efforts in their communities to better understand the ways that AFC efforts can catalyze local leaders – including older adults themselves – towards impact on ageing.