Acute exercise benefits memory, and the temporal placement of exercise relative to exposure can affect the magnitude of benefits observed. Although the temporal placement appears to be important, there is a limited understanding as to how cognitive benefits in response to acute exercise are achieved. Hence, we conducted a two-part study including a behavioral study and a follow-up functional magnetic resonance imaging (fMRI) study to advance our understanding of the potential role of the effects of exercise on memory and neural activation. For Study One, we assessed the effect of acute exercise on memory in young adults. Participants were randomized to exercise before exposure for 20 min (before only, BO), after exposure for 20 min (After Only, AO), before and after exposure for 10 min at each time (before and after, BA), or to receive no exercise (No-exercise Control, NC). Similar to previous findings, any exercise prior to exposure (BO, BA) benefited some aspects of memory performance. Interestingly, the more consistent and larger benefits were seen with a shorter duration of exercise both before and after exposure (BA). Study Two replicated the methods of Study One comparing the BA condition (which had the most robust benefits) to the NC condition while collecting fMRI data during the memory task. Analyses assessed condition differences of activation during encoding and recall. There were no condition differences during memory encoding, however there was a condition effect on activation in occipito-temporal regions during the memory recall trials. Consistent with previous research, exercise appears to benefit memory with some exercise prior to exposure being important for the benefits achieved. Further, exercise affects neural activation and the results appear complementary to the behavior findings. Future research should use a within-subjects design to control for heterogeneity in behavior and neural activation.