Kammala jumla mai zuwa: Corbet ya tsere a 1803 kuma ya koma Faransa. An nada shi farfesa na Ingilishi a kwalejin soja na St Cyr. Daga baya a wannan shekarar ya zama Kyaftin a cikin Irish Legion. Bayan mutuwar ɗan'uwansa Thomas (wanda kuma yana cikin Legion) a cikin duel tare da wani jami'in, an canza shi zuwa 70th Regiment na layin, inda ya yi aiki a cikin tafiyar Massena zuwa Fotigal, kuma ya bambanta kansa a cikin koma baya daga Torres Vedras da yakin Sabugal. Bayan yakin Salamanca an nada shi chef de bataillon na rundunar 47 kuma ya yi aiki har zuwa 1813 lokacin da aka kira shi zuwa Jamus don shiga ma'aikatan Marshal Marmont. Ya yi aiki a yaƙe-yaƙe na
Lutzen, Bautzen, Dresden da sauransu kuma an sanya shi kwamandan rundunar Legion of Honor. A watan Disamba na 1814, an ba shi izinin zama ɗan ƙasar Faransa. A 1815, bayan da Napoleon ya yi watsi da shi, an ba shi mukamin colonel kuma shugaban ma'aikata ga Janar d'Aumont a Caen.