Justinian was born in 482. He ruled from 527 until his death, in 567. He became komes ton domestikon in 518 and acquired the title of patrician. He took up the office of hypatos in 521, which increased his prestige and power in the capital city circles. He later became supreme officer in the imperial guard. He was appointed co-emperor in 527 and remained the sole emperor within the same year, after Justin's death. Thanks to his physical endurance and few hours of sleep he was termed "the sleepless king" in an inscription of the Saints Sergius and Bacchus church as well as "the lord of daemons" according to Procopios the historian. He was a domineering person, capable of great insistence, discipline and patience in order to achieve his goals. He was also particularly active and industrious, good mannered, not prone to recklessness, but also rather incredulous.

His portrait survives in a mosaic at the church of San Vitale at Ravenna as well as on contemporary coins.

Justinian died on November 14, 565. His ambitious agenda was imbued with the spirit of an all-powerful, restored Roman Empire, as well as with the effort to establish Orthodoxy. Yet, many were those who criticized his financial policy because of the long wars his many ambitious building projects, which cost huge amounts of money to the state. Also, new problems were felt in the Northern and Eastern borders at the same time that tension appeared in the Eastern provinces. Nevertheless, his reorganization of the Empire, his legislative work, the restoration of the Roman Empire and, last but not least, the flourishing arts and letters were all characteristic of the thirty-eight years of Justinian's constructive rule.