Adam Clarke on 1 Chronicles 9:11

The ruler of the house of God - The high priest at this time was Jeshua the son of Jozadak, (Ezr 3:8), and Seraiah, (Neh 11:11), called here Azariah, was the ruler of the house; the person next in authority to the high priest, and who probably had the guard of the temple and command of the priests, Levites, etc. It is likely that the person here was the same as is called the second priest, 2Kgs 25:18 (note), who was the sagan or high priest's deputy. See the note there.