Abu Bakra's brother-in-law Utba ibn Ghazwan al-Mazini had established the initial camp at Basra in 635 and was the founder and first governor of the city. The administrative skills of Ziyad became apparent from the time of his adolescence and Utba charged him with minor tasks in the Basran "dīwān" (bureaucracy) during the reign of Caliph Umar (). In 635, Utba tasked him with distributing to the Arab troops the war spoils from the capture of al-Ubulla (Apologos), a town immediately east of Basra. According to the modern historian Isaac Hasson, Ziyad "distinguished himself as an intelligent and open-minded secretary, who was devoted to his master and to public service ... he showed an unusual aptitude for accounting and had an excellent command of epistolary art". His skills and his assignment by Basra's military governor Abu Musa al-Ash'ari as his acting replacement while he was on a military campaign gained the attention of Caliph Umar. He brought Ziyad to Medina, the center of the nascent Muslim state, where he further tested his skills; Ziyad's performance earned him a reward of 1,000 silver dirhams by Umar, which he used to purchase the freedom of his mother or his stepfather Ubayd. Soon after his return to Basra, Ziyad was made Utba's "kātib" (scribe or secretary). After Utba's death, Ziyad continued his service as "kātib" under his successors Abu Musa al-Ash'ari and al-Mughira ibn Shu'ba, a member of the Thaqif who became Ziyad's mentor. When al-Mughira was recalled by Umar to Medina in 638 due to charges of adultery by three accusers, including Abu Bakra Nufay and a certain Shibl ibn Ma'bad al-Bajali, both of whom were Ziyad's maternal half-brothers, Ziyad was also recalled to give his own testimony. His statement was partial toward al-Mughira and as a result, the charges were dismissed and the accusers were flogged. During the reign of Caliph Uthman (), Ziyad served the caliph's appointee to Basra, Abd Allah ibn Amir. Uthman's successor Ali () appointed Abd Allah ibn Abbas governor of Basra and entrusted Ziyad with collection of the province's "kharāj" (land tax) and supervision of the treasury.