Ka kammala wannan magana: A lokacin da yake ƙuruciyarsa, ya girma a fadar Sweden tare da 'yar uwansa Sarauniya Christina, ya sami kyakkyawan ilimi na farar hula. Daga baya Charles X ya koyi fasahar yaƙi a ƙarƙashin Lennart Torstenson, yana kasancewa a karo na biyu na Breitenfeld (1642) da kuma a
Jankowitz (1645). Daga 1646 zuwa 1648 ya halarci kotun Sweden, wanda ake zaton shi ne mijin da zai iya zama dan uwansa sarauniya mai mulki, Christina na Sweden (1626-89, ya yi sarauta 1632-54), amma rashin amincewarta da yin aure ya kawo ƙarshen waɗannan tsammanin, kuma don biyan dan uwanta don karya alkawarin rabin alkawari ta bayyana shi a matsayin magajinta a 1649, duk da adawa da Privy Council wanda Axel Oxenstierna ya jagoranci. A shekara ta 1648 ya sami mukamin kwamandan sojojin Sweden a Jamus. Kammalawa na yarjejeniyar Westphalia a watan Oktoba 1648 ya hana shi cin nasarar laurels na soja da aka ce yana so, amma a matsayin wakili na Sweden a majalisa na Nuremberg, yana da damar da za ta koyi diplomasiyya, kimiyya da aka kwatanta da shi da sauri. A matsayinsa na magajin gadon sarauta, matsayinsa a kan dawowarsa Sweden yana da haɗari saboda rashin jin daɗin sarauniyar. Saboda haka ya koma tsibirin Öland har sai da Christina ya yi watsi da shi a ranar 5 ga Yuni 1654 ya kira shi zuwa kursiyin.