Several inscriptions of Lugal-ushumgal are known, particularly seal impressions, which refer to him as governor of Lagash and at the same time a vassal (𒀵, arad, "servant" or "slave")[8] of the Akkadian Empire rulers Naram-Sin and his successor Shar-Kali-Sharri.

[16] The inscription carries two blocks of columns: 𒀭𒈾𒊏𒄠𒀭𒂗𒍪 𒁕𒈝 𒀭𒀀𒂵𒉈𒆠 𒈗 𒆠𒅁𒊏𒁴 𒅈𒁀𒅎 𒈗𒃲𒁔 𒁾𒊬 𒑐𒋼𒋛 𒉢𒁓𒆷𒆠 𒀵𒋢 DNa-ra-am DSîn da-num Da-ga-deki lugal ki-ibradim arbaim lugal-ušumgal dub-sar ensi lagashki arad2-su

"Naram-Sin, the mighty God of Agade, king of the four corners of the world, Lugalushumgal, the scribe, ensi of Lagash, is thy servant.

[22] The inscription carries two blocks of columns: 𒊬𒂵𒉌 𒈗𒌷 𒁕𒈝 𒈗 𒀀𒂵𒉈𒆠 𒈗𒃲𒁔 𒑐𒋼𒋛 𒉢𒁓𒆷𒆠 𒀵𒋢 Shar-kali-sharri da-num lugal a-ga-deki lugal-ušumgal ensi lagashki arad2-su

"Shar-kali-sharri, the mighty king of Agade, Lugalushumgal, ensi of Lagash, is thy servant."