Traditionally, marketing of sustainable products addresses green buyers, thus missing out on the mainstream consumers and volume necessary to cover the potentially higher cost of more sustainable materials. However, how to effectively communicate more sustainable products to mainstream consumers and to increase their buying intention is still underexplored. Combining personal and environmental benefits, called double benefit theory, is promoted as an effective green marketing strategy but so far not supported by quantitative research as being effective to reach mainstream consumers. We studied the effect of advertisement elements (layout color, benefit type, and heritage) on the products’ perceived sustainability, quality and fashion image, and buying intentions of mainstream consumers. Two hundred adults participated in a study that was based on a 2 (red vs. green layout) × 2 (personal vs. environmental benefit) × 2 (local vs. global heritage) between-subjects factorial design of a sustainable shoe advertisement. The impact of these independent variables on product image as well as on buying intention was analyzed by means of three-way ANOVAs. In line with the double benefit theory, combining a personal benefit with a green layout led to the highest buying intention. Moreover, a mediation analysis revealed the effect of emphasizing a personal benefit on buying intention was mediated by fashion image but not by sustainability. Sustainability, however, did have a positive effect on buying intentions independent of benefit type.