Sargon of Akkadia was the exception of Sumer. Reigning over Sumer from about 2334-2279 BC, he was not actually of Sumerian origin. Rather, he was of Semitic background, as the Akkadians originally hailed from the Arabian Peninsula before settling down in Mesopotamia. Aside from establishing Sumer's first and only Semitic dynasty, Sargon is credited with being the founder of the Mesopotamian military tradition, establishing history's first empire, the Akkadian Empire.
As there has been precious little found in the way of contemporary records, most of what we know about Sargon, is by way of legends.
According to at least one legend, Sargon was of humble origin with his father being totally unknown. Allegedly, he was found in a basket floating in the river by a gardener who chose to adopt and raise him as his own son, much as Moses would be many years later. His lack of important relations notwithstanding, he attained that position of cup-bearer to the ruler of Kish.
Sargon's time to rule came with the collapse of the Lagash Dynasty, and Lugalzaggisi's subsequent defeat at the hands of Sargon. Things being what they were at the time, Sargon then had to re-conquer every city that had been under Lugalzaggisi's control. Ultimately his control extended to northern Syria, western Iran, into Lebanon and possibly into parts of Greece.