This study investigates the relation between age and sustainability awareness for consumers via the third, mediating variable of influencers to reduce the intention-behaviour purchase gap. It proposes that traditional theories of planned behaviour are limited as they do not account for unconscious and indirect pathways to axiological change. A structural model with the 3 constructs of age, influencers, and sustainability awareness is tested with linear structural relations on a sample of 788 consumers, complemented with focus groups and interviews to generate deeper insight into the model's constructs. The results demonstrate a relationship between age and sustainability awareness, as well as between the importance of influencers for increased sustainability awareness in younger consumers, namely, millennials. This suggests that practitioners should work with influencers perceived as trustworthy to increase sustainability awareness for the millennial subset consumer group. The methodology applies a mixed approach, interpreting both qualitative and quantitative aspects, and contributes to the ethical consumerism literature with new knowledge on age differences connected to sustainability awareness, particularly highlighting on the influence of influencers for the younger generations.