Individual behavioral phenotypes (personality traits) are predicted to influence an animal’s diet and maybe linked to its stress physiology because different behavioral phenotypes perceive and react differently to similar stimuli. Here we studied free-ranging common brushtail possums to test whether their diets differ as a function of their personality and to interpret this relationship in terms of stress physiology. We predicted that pro-active (bold, exploratory, active) animals would have a higher quality diet because they had more diverse foraging opportunities, such as foraging more on the ground and in gardens where predation risk is higher. We studied 30 possums on the urban boundary with open eucalypt forest in Ku-ring-gai Chase National Park, Sydney Australia. We quantified the personality of each animal along three axes: exploration, boldness and activity; and collected their scats to determine diet using micro-histological and DNA barcoding methods. In a separate study with animals brought into captivity, we quantified stress hormone levels and compared these to personality traits. Our results show that the diet of individual possums is strongly influenced by personality (exploration, boldness and activity). Diet of exploratory individuals was twice as diverse as that of less exploratory individuals. Diet diversity was also related to boldness and activity. We report on the correlation with stress hormone levels across a proactive-retroactive continuum. Given that the personality of different animals leads to different choice of foods within the same landscape, we predict that herbivore impact on plant communities will vary according to individual phenotype.