It is possible he usurped the throne from Urtarsirsira, a distinguished son of Lugalanda. However he continued to live in the first year of Urukagina's reign.

Urukagina was the last Old Sumerian ruler of Lagash before its conquest by Lugalzagesi of Umma and the subsequent Sargonic period. His reign witnessed a gradually shrinking sphere of political power under threat from both Uruk and Umma, that at one point forced him to abandon Lagash and move his capital to Girsu. At the same time, he instituted a well-known series of reforms that attempted to rebalance some of the economic iniquities between the poor and elite social classes.

On the regional level, Urukagina faced military danger from others before the final threat by Lugalzagesi. Numerous administrative texts attest to repeated attacks by Uruk upon the Lagash state. (DP 545), for instance, mentions a siege by the man of Uruk upon the city, which Bauer takes to mean Girsu (Bauer pg. 479). Another administrative text (NIK 1, 227) is dated to the 'month that the man of Uruk came a third time'. These inter-city attacks demonstrated the widening scope of military campaigns in southern Mesopotamia and the resulting political entities that grew out of them. Already before Sargon and Lugalzagesi, Enshagkushana of Uruk claimed the titles 'lord of Sumer' (en ki-en-gi) and 'king of the land' (lugal kalam-ma), having conquered Kish and Akshak, and even besieging Akkad (Bauer pg. 480).

However it was Lugalzagesi who dealt the crippling blow to the Lagash state in the seventh year of Urukagina's reign (Bauer pg. 494). One surviving Lagash text ([[http://cdli.ucla.edu/P222618| FAOS 05/1, Ukg. 16) describes in dramatic fashion how Umma destroyed many public works and pillaged many sacred sites of the state, including the Antasura, the Tirash temple of Ningirsu, the Ebabbar, the Ibgal of Inana, and the temple of Gatumdug. Other, administrative texts, give a more subdued account of the waning of Lagash's power, as they indicate a general reduction in the economic vitality and manpower of the state. See, for instance, ([[http://cdli.ucla.edu/P221396| TSA 35), dating to the end of Urukagina's 5th year, and ([[http://cdli.ucla.edu/P221826| NIK 1, 57), dating to the beginning of the 6th.