Hammurabi became king of Babylon in the early eighteenth century BCE, conventionally dated to 1792 in the middle chronology. He inherited a kingdom that was one of several competing powers in Mesopotamia. Early rule combined alliances, limited campaigns and work on infrastructure rather than an immediate conquest of the whole region. Royal inscriptions emphasize canals, fortifications and religious building, presenting practical administration through the language of service to gods and subjects. Such claims reveal ideals of kingship as well as particular activities.

In the later part of his reign, diplomacy and military action enlarged Babylon's power. He cooperated with other rulers against shared threats, then overcame rivals including Larsa, Eshnunna and Mari. Relations with Zimri-Lim of Mari changed from alliance to domination, and the destruction of Mari demonstrated the coercive foundation of the new order. Control of waterways, agricultural resources and routes supported conquest and government. The realm was extensive, but its territorial unity proved fragile after his death.

The monument conventionally called the Code of Hammurabi associates him with justice under divine authority. Its judgments cover property, contracts, family relations, labour, injury and professional responsibility. Penalties differ according to status, sex and the nature of the case; equality before law in the modern sense is not its organizing principle. The collection was not the earliest Mesopotamian legal text and does not simply operate like a comprehensive statute book governing every court. Its relationship with everyday judicial practice remains a subject of study. The prologue and epilogue also proclaim the king's achievements and instruct later readers about legitimate rule.

Correspondence and administrative evidence show a ruler involved in officials' conduct, labour, land and the maintenance of royal interests. This makes his career broader than the popular image of a man who only issued laws. He died around 1750 BCE, succeeded by Samsu-iluna, whose reign faced rebellions and loss of territory. Later copying preserved his legal collection as a learned and royal model long after the original political circumstances changed. His importance rests on the expansion of Babylon and the articulation of justice as a responsibility of kingship, while both conquest and the hierarchy built into the judgments qualify later celebrations of him as a universally fair lawgiver.