Constantine's reign was marked by prodigality, enjoying an abundant imperial treasury following the conquests of his predecessors and the era of economic expansion that the Empire experienced in the first half of the 11th century.

Despite the varying success of these campaigns, the Byzantine Empire largely retained the borders established after the conquests of Basil II (r. 976–1025), even expanding eastwards when Constantine annexed the wealthy Armenian kingdom of Ani.

In 1054, a year before Constantine's death, the Great Schism between the Eastern Orthodox and Roman Catholic Churches took place, culminating in Pope Leo IX excommunicating the Patriarch Michael Keroularios.

[6] Constantine's position improved after he married his second wife, sometimes called Helena or Pulcheria, a daughter of Basil Skleros,[7] and niece of Emperor Romanos III Argyros.

[8] Catching the eye of Empress Zoë Porphyrogenita, he was exiled to Mytilene on the island of Lesbos by her second husband, Emperor Michael IV.

[10] However, before he could commence his appointment, Constantine was summoned to Constantinople, where the fragile working relationship between Michael V's successors, Empresses Zoë and Theodora Porphyrogenita, was breaking down.

[19] As part of the peace negotiations, Constantine married his daughter, Anastasia (by his second wife or Maria Skleraina), to the future Prince Vsevolod I of Kiev, the son of his opponent Yaroslav I the Wise.

[5][22] Constantine IX's preferential treatment of Maria Skleraina in the early part of his reign led to rumors that she was planning to murder Zoë and Theodora.

[34] Constantine seems to have taken recourse to the pronoia system, a sort of Byzantine feudal contract in which tracts of land (or the tax revenue from it) were granted to particular individuals in exchange for contributing to and maintaining military forces.

[39][40] He was persuaded by his councillors, chiefly the logothetes tou dromou John, to ignore the rights of the elderly Theodora, daughter of Constantine VIII, and to pass the throne to the doux of Bulgaria, Nikephoros Proteuon.

Psellos left a physical description of Constantine in his Chronographia: he was "ruddy as the sun, but all his breast, and down to his feet... [were] colored the purest white all over, with exquisite accuracy.

"[44] Immediately upon ascending to the throne in 1042, Constantine IX set about restoring the Church of the Holy Sepulchre in Jerusalem, which had been substantially destroyed in 1009 by Caliph al-Hakim bi-Amr Allah.

[45] Byzantine Emperor Romanos III had secured the right to undertake such a restoration in a treaty with al-Hakim's son al-Zahir, but it was Constantine who finally set the project in motion, funding the reconstruction of the Church and other Christian establishments in the Holy Land.

[47] He was described by Michael Psellos as "a marvel of beauty that Nature brought into being in the person of this man, so justly proportioned, so harmoniously fashioned, that there was no one in our time to compare to him".

[4] For example, he gave to the Church many objects of great value, including precious sacred vessels, "that surpassed by far all the others as to dimensions, beauty and price".