Objectives: For schools to consider physical activity (PA) interventions, improvements must be shown in PA and additional educational benefits such as executive function (EF) and academic performance (AP). Over 8,800 schools worldwide have implemented The Daily MileTM (TDM), without any formal assessments of its impact. Rigorous and high-quality studies are needed to explore TDM’s contribution to moderate-to-vigorous PA (MVPA) guidelines and potential impact on EFs and AP. Methods: Children (14 classes, n=303, age mean=8.99±0.5) from 11 primary schools already implementing TDM consented. At the individual level, children were randomly assigned using a 4-block process to either TDM or continued academic lessons (TDM n=158, control n=145). Children completed pre and post, EF tests (Trail Making Task; Digit Recall; Flanker; Animal Stroop) and a maths fluency test (Maths Addition and Subtraction, Speed and Accuracy Test). Accelerometers assessed MVPA using 15-second-epochs and Evenson cut-points. Results: Using multi-level modelling, TDM revealed significantly greater MVPA (+10.23 minutes) and reduced sedentary time (-9.28 minutes) compared to control (p≤0.001, d=4.92, 3.61 retrospectively). Maths fluency interacted with condition and time (p=0.031, d=0.25); post hocs revealed no significances over time (p>0.05). No differences in EFs (all p>0.05). Conclusions: This study is the first assessing the acute effects of TDM compared to continued academic lessons. TDM revealed no significant improvements in maths fluency or EF. These findings question justifying the widespread adoption of TDM based on enhanced cognition claims. Nonetheless, TDM may provide 10 minutes of MVPA, achieving a third of the daily in school recommendations to meet overall daily recommendations.