The current research explored the thesis that cognitive self-recognition might have an executive function in 3- and 4-year-olds. Although it is well established that children recognise themselves in mirrors by the end of infancy, the cognitive and behavioural impact of this capacity has yet to be elucidated. Experiments 1 to 6 showed that preschool children could form and maintain a cognitive link between the self and external stimuli, as a result of which, self-referent stimuli were given mnemonic priority. Experiments 4 to 8 indicated that in tasks involving self-recognition, 3- and 4-year-olds’ ability to process other-referent stimuli was compromised by self-focus. Finally, Experiments 9 and 10 demonstrated that mirror self-recognition increased preschoolers’ tendency to self-regulate, leading them to behave in line with socially accepted standards. Together, these experiments provide novel evidence to confirm that cognitive self-recognition has a role in preschoolers’ performance on tasks requiring memory, attention, inhibition, and planning. This implies that when salient, the self may become the ultimate executer of behaviour. By observing 3- and 4-year-olds’ differential processing of self- and other-referent stimuli we infer the existence of a functionally active, self-reflective agent. Moreover, the role of the self is temporally extended, influencing children’s cognition and behaviour in the past (Experiment 1 to 3), present (Experiments 4 to 8) and future (Experiments 9 to 10). This implies that preschool children may have developed the foundations necessary to build the experience of personal identity