The measurement of societal wellbeing has moved beyond gross domestic product and has emerged as an important factor within the paradigm of holistic sustainability assessment, including agricultural sustainability. At this juncture, knowledge gaps exist between agricultural policy priorities and data infrastructure to evaluate social sustainability issues, particularly regarding farmer sustainability. This study aims to address this gap through the development of a Farmer Sustainability Index (FSI), a composite index comprising three dimensions: farm continuity, community and social connections and farmer comfort. Socio‐demographic data were extracted from both core and supplementary EU Farm Accountancy Data Network data from the 2018 Teagasc National Farm Survey in Ireland. Statistical analysis was undertaken to compare the distribution of FSI and the individual dimension scores for farms across three socio‐demographic variables: farm system, farmer age cohort and region. The FSI results demonstrate that cattle farmers, farmers over 60 years of age and those residing in regions with poorer infrastructure experience lower levels of sustainability in comparison to other farmers, while the variation in FSI dimension scores identifies numerous sustainability risks to farms with differing socio‐demographic constructs. It is important for agricultural policy to be cognisant of these differences and the relational nature of these risks, to meaningfully address matters pertaining to sustainability, and the FSI provides an effective tool to assist policy in this regard.