As producers of economic and cultural goods, media companies are subject to a double responsibility: regarding how they operate and how they represent reality in their products. Thus, their social responsibility is primarily the “brain print” they leave on their audience. Communication of, about, and for sustainability through mass media is therefore essential to create a shared understanding of societal values on sustainability, creating public engagement, and contributing to sustainable development. Accordingly, the present study aims at understanding how media (companies) take their responsibility as key communicators in the public sphere and analyze how they communicate and thus construct the sustainability discourse through their products. For this, sustainability-related content produced and broadcasted by the two largest commercial media companies in Germany (RTL and ProSiebenSat1; n = 50 online articles and n = 89 videos, 601 min in total) was analyzed by qualitative content analysis and rhetoric text analysis to understand what and how media communicate sustainability. Results show that most media sustainability-related content addresses food issues, followed by issues regarding resources and the environment, thus contributing to the achievement of some of the 17 Sustainable Development Goals (SDGs). Namely: SDG#2 (zero hunger), #6 (clean water and sanitation), #13 (climate action), #14 (life below water), and #15 (life on land). These issues are primarily communicated logically, appealing to the audience’s reason (logos, 76%), while the ethical appeal ethos (22%) and the emotional pathos (2%) scarcely occur. The analysis also leaves room for discussion regarding the responsibility of media companies in their role as communicators of, about, and for sustainability; about how they fulfill their responsibility in accordance with the SDG Media Compact, and about the opportunities and risks of applying different rhetorical appeals.