This study aims to investigate metaphors of pre-service teachers, the potential future educational leaders, regarding sustainability according to their knowledge level of sustainability. The study utilized the convergent research method, one of the mixed-method research designs based on both quantitative and qualitative data. The participants consisted of 867 pre-service teachers from different departments of the Faculty of Education in a public university in Turkey. The data were collected via "The Knowledge Test" developed by (Gökmen, 2014) and "The Metaphor Determination Form" (Yildirim, 2013), whose reliability and validity studies were also conducted. Cluster analysis was used to analyze the quantitative data and the pre-service teachers were categorized according to their knowledge level of sustainability. Content analysis was used to analyze the qualitative data and using the results obtained the pre-service teachers' metaphors were categorized. The results revealed that the pre-service teachers' knowledge levels of sustainability were above the middle-level. The cluster analysis results showed that the pre-service teachers were categorized into three groups: low, middle, and high. The pre-service teachers created 32 meaningful metaphors under four different categories (vital, economic, social, and will-o-the-wisp). The results also showed that the metaphors created by the pre-service teachers significantly varied by their knowledge level of sustainability.