Nyorai kupfuurira kweiyi ndima - Clarke akanga ari mumwe wevakuru vane simba zvikuru uye vane rudo veFrance neIreland muuto reFrance munguva yaNapoleon. Aiva noukama hwepedyo neIrish Brigade yeFrance. Baba vake vakashanda muDillon's Regiment (uko Clarke pachake akashanda kwechinguva) uye baba vaamai vake uye vanasekuru vanoverengeka vakashanda muClare's Regiment. Nokutanga kweFrench Revolution, Clarke akashanda muhondo dzekutanga dzeFrench Revolutionary muHondo yeRhine, uye muna 1793 akasimudzirwa kuva "général de brigade". Muna 1795 Clarke akasungwa kwenguva pfupi. Mushure mokusunungurwa kwake, Clarke akararama muAlsace kusvikira Lazare Carnot amutumira kuItaly kuti ashande semukuru mukuru weNapoleon Bonaparte, kusvikira atumirwa kuSardinia. Pashure pa18 Brumaire, Clarke akashanda saChief weTopographical Bureau, State Councillor, munyori wehurumende wemauto nehondo. Mukati mehondo yokurwisana neAustria muna 1805, Clarke akagadzwa kuva gavhuna weVienna uye mukati mehondo yokurwisana nePrussia
muna 1806 akashanda samutongi weErfurt neBerlin.