Osorkon II was Takelot I's son and hence Osorkon I's grandson. The problems associated with the Theban pontificate continued, which Osorkon II attempted to alleviate by following the generally accepted practice of appointing a son to an office when it fell vacant, a situation which occurred not infrequently in a family that, with a few exceptions, does not seem to have been especially long-lived.

The king soon proved himself an energetic ruler. He was ruthless in suppressing the aspirations of rival claimants to the High Priesthood in Thebes; Harsiese in particular troubled him and, on the latter's death, Osorkon appointed one of his sons, Nimlot, as High Priest in Thebes. He built very widely and was responsible for many works of high quality. He celebrated his jubilee in his twenty-second regnal year, an occasion of rejoicing throughout all Egypt. This jubilee was proclaimed by one of the leading clerics, Bakenkhons, who was deeply conscious of the honor done to min.

Osorkon II was active in promoting closer relations with Egypt's neighbors and in seeking alliances against the rising power of Assyria. One such alliance was with the kings of Israel.

Nonetheless, Osorkon II maintained reasonable relations with the Assyrians; in the last years of his reign other claimants to the kingship of Egypt appeared, with whom Osorkon does not appear to have been inclined to quarrel.

Osorkon is commemorated in one of the smaller though undoubted masterpieces of Egyptian craftsmanship, the so-called "Osorkon Triad", a jewel-like object comprising the god Osiris (possibly a portrait of Osorkon) crouching on a lapis lazuli column, supported by Horus and Isis. The gods are all fashioned in gold.