Rubuta ci gaba don wannan sakin layi - Daga kusan 'yan jarida 300 a cikin ajinsa, kuma duk da kammala dukkan sassan karatunsa cikin nasara, Gary ne kawai ba a ba shi izini a matsayin jami'i ba. Ya yi imanin cewa tsarin soja ba shi da tabbaci ga abin da suka gani a matsayin baƙo da Bayahude. Horarwa a kan Potez 25 da Goëland Léo-20 jirgin sama, kuma tare da sa'o'i 250 na lokacin tashi, kawai bayan jinkirin watanni uku aka sanya shi sajan a ranar 1 ga Fabrairu 1940. An ji rauni a ranar 13 ga Yuni 1940 a cikin Bloch MB.210, ya yi baƙin ciki da yarjejeniyar armistice
Bayan jin kiran da Janar de Gaulle ya yi ta rediyo, sai ya yanke shawarar zuwa Ingila. Bayan yunkurin da ya kasa, ya tashi zuwa Algiers daga Saint-Laurent-de-la-Salanque a cikin Potez. Ya zama mai taimakawa bayan ya shiga Free French kuma ya yi aiki a Bristol Blenheims, ya ga aikin a fadin Afirka kuma an ci gaba da zama na biyu. Ya koma Ingila don horar da shi a Boston IIIs. A ranar 25 ga Janairu, 1944, matukin jirgi ya makance, kodayake na ɗan lokaci, kuma Gary ya yi magana da shi zuwa makasudin fashewar bama-bamai da dawowa gida, saukowa ta uku ta yi nasara. Wannan da kuma tattaunawar BBC da ta biyo baya da kuma labarin jaridar Evening Standard wani muhimmin bangare ne na aikinsa. Ya ƙare yakin a matsayin kyaftin a ofisoshin London na Free French Air Forces. A matsayin mai lura da bom a cikin "Groupe de bombardement Lorraine" (No. 342 Squadron RAF), ya halarci sama da 25 da suka yi nasara, inda ya yi sama da awanni 65 na iska. A wannan lokacin, ya canza sunansa zuwa Romain Gary. An yi masa kwalliya saboda jaruntakarsa a yaƙin, yana karɓar lambobin yabo da girmamawa da yawa, gami da Compagnon de la Libération da kwamandan Légion d'honneur. A cikin 1945 ya buga littafinsa na farko, "Education européenne". Nan da nan bayan hidimarsa a yaƙin, ya yi aiki a cikin sabis na diflomasiyyar Faransa a Bulgaria da Switzerland. A shekara ta 1952 ya zama sakataren Wakilin Faransa a Majalisar Dinkin Duniya. A shekara ta 1956, ya zama Consul Janar a Los Angeles kuma ya zama sananne ga Hollywood.