Wasif was originally a slave ("ghulam") and was owned by the Nu'man family in Baghdad, where he worked as an armorer. At some point he was purchased by the future caliph al-Mu'tasim (r. 833–842), and he soon rose to prominence as a member of the Abbasids' new Turkish corps. When al-Mu'tasim decided to move his capital to Samarra in 836, Wasif and his followers were settled in the new city, having received land allotments adjacent to al-Hayr. In 838 Wasif participated in al-Mu'tasim's Amorium campaign, and is mentioned as commanding the caliph's advance guard as they passed through the Gates of Tarsus. According to al-Ya'qubi, Wasif also served as al-Mu'tasim's chamberlain ("hajib").