Kammala wannan jumla: Gilmour ya shiga Lovat Scouts a 1937 inda ya sami kwamishinsa. Daga nan sai ya shiga cikin Seaforth Highlanders a 1939. Tsakanin 1942 da 1943, ya kasance tare da 2nd Seaforth a cikin 51st Highland Division na 8th Army a yakin Arewacin Afirka. An ba shi lambar yabo ta Soja a karo na biyu na El Alamein, tare da Bar zuwa MC don ƙarin nuna ƙarfin hali a gaban Jamusanci Afrika Korps a
Yaƙin Wadi Akarit. Ya shiga cikin mamayewar Sicily. Ya koma Birtaniya a 1943. Daga 1944, ya yi aiki a Normandy, Netherlands, da kuma Jamus inda ya sami Gicciye na Musamman daga Amurka.