Emerging evidence indicates that acute exercise improves executive function, but its effects on higher-order executive functioning skills among people with a risk of Alzheimer’s disease are not well understood. This study addressed the effects of acute exercise on the planning dimension of executive function among late middle-age adults who carried Apolipoprotein (APOE)-ɛ4. Exercise volume was kept constant, but exercise intensity and duration were manipulated. Eighteen adults in the age range 55–70 years who carried APOE-ɛ4 were recruited for a laboratory-based study set in a within-subjects, counterbalanced design. There was a reading control condition along with three exercise conditions: Acute cycle exercise at a moderate intensity for 30 min (MI-30); higher intensity exercise of a shorter duration (16 min); and lower intensity exercise of a longer duration (40 min). Exercise volume was set with reference to energy expenditure in MI-30. The Tower of London Test was administered at the end of each condition. Acute aerobic exercise improved cognitive performance in regard to move-related scores and time-related scores, but not violation-related scores, when compared to the control condition. There was no difference in terms of the facilitation effect among the three exercise conditions. The present findings indicate that acute aerobic exercise, regardless of intensity/duration manipulation, facilitates higher-order executive function in late middle-aged APOE-ɛ4 carriers. Practitioners should, accordingly, consider exercise as a suitable intervention for those at risk of Alzheimer’s disease.