Rubuta ci gaba don wannan sakin layi - McLeay ya shiga cikin Sojojin Australiya (AIF) a watan Mayu 1915. Ya yi aiki tare da rukunin likitoci a Gabas ta Tsakiya da kuma Yammacin Yamma. Yayin da yake zaune a Faransa a matsayin mai ɗaukar hoto tare da 13th Field Ambulance, an ba shi lambar yabo ta soja don jaruntaka a ranar farko ta Yaƙin Villers-Bretonneux na biyu
a watan Afrilu na shekara ta 1918. An sallame shi daga aikin soja a watan Oktoba 1919.