His father Pan Kul Tigin was a shad (governor) of the empire during the reign of Bilge Kutluk Khagan.
Although Pan Kül Tigin had staged a successful coup against Kutluk Bilge, he was killed during a battle against Ashina Shi and his Basmyls.
Following a short and turbulent term where Kutlug Yabgu Kagan tried to restore the authority without success, Özmiş was elected as the new khagan in 742.
The policy of Tang China was to vassalize all people to the north of Chinese border line and Özmiş was also expected to pay respect.
Wang Zhongsi organized a coalition of three Turkic people Basmyl, Uighur and Karluk, who had previously accepted the suzerainty of Chinese emperor, instead of Özmiş.