Over the last years, we could observe increasing awareness of sustainability and climate change in society. Individual sustainable behavior emerges by various influencing factors, resulting in different degrees of sustainable behavior. An important factor is the intention behind pro-environmental behavior, which can be goal-directed, motivated by other goals, or habitual. At the same time, good intentions do not always translate into sustainable actions. To develop interventions that promote pro-environmental behavior, we need to shed light on cognitive mechanisms underneath sustainable thoughts and how they stimulate actions. We conducted ten semi-structured interviews with representative individuals asking about their intentions, influencing factors of sustainability and examples from everyday life. Based on their scope of reflection, knowledge, and predominant intention, we could identify five different sustainability personas: sustainability-oriented, open-minded, opportunistic, careless, and dismissive. We present characteristics of these personas, discuss the validation process, and investigate cognitive mechanisms of reflection in the context of sustainable behavior.