By his Year 6, the distant authority of Shoshenq III Sibaste was recognized at Thebes, with the High Priest of Amun Harsiese "B" dating to his reign, having temporarily displaced Takelot II Siese's son Osorkon.

Shoshenq III's son, the General Pashedbaste "B", restored the foregate of Pylon X at Karnak, dating by the regnal count of Padubaste I, although the year is lost.

[23] Whether as partner or rival of Shoshenq III Sibaste, Padubaste I is attested by his subjects' dedications at Memphis, and a donation stele at Bubastis.

[27] Shoshenq III Sibaste ruled throughout Lower Egypt, and in his Year 26 also at Heracleopolis, whose military commander Bakenptah is recorded as a brother of the High Priest of Amun Osorkon.

[28] Although the Libyan chieftains continued to defer to the king's authority, it appears that in this period they began to surpass their original function as garrison commanders by becoming more involved in and controlling larger territories.

[32] The Libu might have been settled in the western Delta during the reign of Shoshenq III Sibaste, and they seem to have been united under the authority of a single chieftain, Inamunnifnebu, by Year 31.

[33] The name of Shoshenq III Sibaste appears throughout Lower Egypt, often in relation to building projects, for example at Tell Umm Harb, Bendariyah, Tell Balamun, and Kom el-Hisn.

The main focus of his activity was the capital Tanis, where he opened a new monaumental gateway in the brick wall of the enclosure of the Temple of Amun, and where he also built his tomb (NRT V), using a simple design.

[34] At Memphis, where the king built a chapel to the goddess Sekhmet,[35] Apis Bulls were buried in perhaps Year 4 and in Year 28, and a stele commemorating the latter was set up by king's probable nephew, the Great Chief of Ma Pediese, son of Takelot "B", and Pediese's sons the High Priest of Ptah Peftjauawybaste and the Sem Priest of Ptah Takelot.