This paper argues that family relations factored into the political appointment of Abu Hadir al-Usayyidi as governor of the Istakhr district, by showing that the accounts concerning Abu Hadir al-Asadi (i.e., of the tribe of Asad) and Abu Hadir al-Usayyidi (i.e., of the Banu Usayyid of Tamim) refer to the same person, who was in fact a member of the tribe of Tamim. Abu Hadir al-Asadi and Abu Hadir al-Usayyidi are linked in the Muslim sources to Istakhr in different ways, and when the accounts of these links are put together, they enrich our knowledge about administrative practices in the early Islamic period. More specifically, Abu Hadir al-Asadi was reportedly scolded by Mus’ab ibn al-Zubayr (d. 72/691) with the words “you son of a woman from Istakhr,” while Abu Hadir al-Usayyidi was appointed by Hajjaj ibn Yusuf (d. 95/714) as governor of that same district. The paper thus suggests that (1) Abu Hadir’s maternal relations were behind his appointment over Istakhr, and that (2) his affiliation with Tamim, which had connections with the Persian Empire before and after the advent of Islam, likewise played a role in his selection for this office. The significance of Abu Hadir’s links with Istakhr is enhanced by the fact that we learn about them from two accounts that are entirely independent from one another. Reading these accounts together, the connection between them becomes clear: the population of Istakhr would be more likely to support the appointment of someone with a close link to them to wield authority over them. The Muslim sources do not typically provide reasons as to why a certain person was given an administrative office. The accounts of Abu Hadir can thus be taken as a case study showing that something as simple as correcting a nisba from al-Asadi to al-Usayyidi can advance our knowledge of early administrative practices. More broadly, it demonstrates that familiarity with the various Arab tribes and the groups that comprised them is crucial for the study of the history of the early Islamic period. Abu Hadir is far from being a prominent figure in the Muslim sources, and hence has not hitherto received much scholarly attention. The findings of this paper, which show that there are benefits to collecting the information available in the Muslim sources concerning one individual, will hopefully encourage others to engage in a similar close reading of these sources.