Kammala jumla mai zuwa: Bayan mutuwar mahaifinsa a 1823, ya yi tafiya zuwa Spain inda ya yi gwagwarmaya na ɗan gajeren lokaci a cikin tayar da kayar baya game da mulkin mulkin mallaka na Ferdinand VII; kafin sojojin Faransa suka kama shi. A cikin 1825, yana cikin rukunin masu sa kai da Kanar Charles Fabvier ya ɗauka a Marseille don yin yaƙi a Yaƙin Girka na Independence. Ya isa Nauplion a 1825, da farko yana aiki a cikin sojan doki na Kanar Auguste Regnaud de Saint-Jean d'Angély a matsayin Soja. Myhrberg ya shiga cikin fadace-fadace a Euboea a 1826, sannan ya yi yaƙi a cikin yunƙurin taimako na Siege na Acropolis inda aka ji masa rauni. A shekara ta 1826, an daukaka shi zuwa Laftanar, daga baya ya shiga cikin inda aka sake ji masa rauni. An ji rauni a cikin aiki a karo na uku a cikin yakin Cape Colias, an ci gaba da shi zuwa Kyaftin bayan kammalawa. A watan Janairun 1827, Myhrberg ya zama mataimakin Fabvier, daga baya ya yi aiki a cikin wannan rawar ga Manjo Janar Thomas Gordon da Kanar Carl Wilhelm von Heideck. Myhrberg ya shiga cikin
Yaƙi na Phaleron da kuma Chios expedition inda ya bambanta kansa. A cikin 1829, Ioannis Kapodistrias ya nada Myhrberg a matsayin Kwamandan sansanin soja na Palamidi. Damuwa da karuwar tasirin Jam'iyyar Rasha, Myhrberg ya bar Girka a cikin 1831 don shiga cikin Tashin hankalin Nuwamba na Poland. An san kadan game da wannan lokacin rayuwarsa, bisa ga wani labari na Anders Ramsay, Myhrberg ya yi yaƙi a yakin Ostrołęka. Ya kama shi da Rasha a wani lokaci a lokacin yakin amma ya yi nasarar tserewa zuwa Prussia mai tsaka tsaki, daga baya ya zauna a Faransa.