A Kipchak by origin, he was formerly a freedman of Seljuq sultan Mahmud II (1118-1131) vizier Kamal al-Din al-Simirumi. After Simirumi's murder at the hands of Assassins in 1122, he passed to the hands of sultan, who entrusted his education to certain emir Nasr. After Mahmud's death, he attained to the post of governor of Arran under sultan Ghiyath ad-Din Mas'ud (1134–1152), who also gave late sultan Toghrul II's widow Momine Khatun and appointed Eldigüz to be atabeg of Arslanshah (son of Toghrul).