Usimare Setepenamun Takelot III Si-Ese is Osorkon III's eldest son and successor.

Takelot III served previously as the High Priest of Amun at Thebes.

He was once thought to have ruled Egypt for only seven years until his 13th Year was found on a stela from Ahmeida in the Dakhla Oasis in 2005.

Takelot III served the first 5 Years of his reign as the junior coregent to his father according to the evidence from Nile Quay Text No.14, which equates Year 28 of Osorkon III to Year 5 of Takelot III.

He succeeded his father as king in the following Year.

Takelot is attested by several documents: a donation stela from Gurob which calls him "The First Prophet of Amun-Re, General and Commander Takelot," a stone block from Herakleopolis which calls him 'the Chief of Per-Sekhemkheperre' and king's son by Tentsai, Quay Text No.

13, which equates Year 5 of Takelot III to Year 28 of Osorkon III and Quay Text No.4 which records his Year 6.