Rubuta ci gaba don wannan sakin layi - A watan Afrilu na 1944, ya ba da umurnin rundunar soji ta 2 ga Major General Edward H. Brooks, an nada shi shugaban ma'aikatan Sojoji na Uku, yana sake aiki a karkashin Laftanar Janar George Patton. Gaffey ya yi wannan hidimar a lokacin yaƙin neman zaɓe a Yammacin Turai
, daga lokacin da Sojoji na Uku suka sauka a Faransa a watan Yulin 1944 kuma suka taka muhimmiyar rawa a cikin Operation Cobra da yakin Falaise Gap, wanda ya biyo bayan ci gaban Allied daga Paris zuwa Rhine da yakin Metz. A watan Disamba na 1944 ya maye gurbin Manjo Janar John Shirley Wood a matsayin CG na 4th Armored Division, wanda ya taka muhimmiyar rawa a yakin Bulge, yana taimakawa wajen karya siege na Bastogne. Ya kasance a cikin umurnin sashen har zuwa Maris 1945, zuwa karshen yakin a Turai, lokacin da ya zama CG na XXIII Corps. Ya yi watsi da umurnin XXIII Corps a watan Satumba, lokacin da yakin ya ƙare saboda mika wuya na Japan.