We know about his remarkable and controversial career thanks to his autobiography, inscribed on a well known statue depicting him; the statue, commonly called Naoforo vaticano (Italian for "Vatican naos-carrier") was originally placed in the temple of Neith at Sais likely in Year 3 of Darius I (c. 519 BCE) and is now exhibited inside the Vatican Museums (more precisely in the Museo Gregoriano Egizio) of Rome.
[1]: 166 Early in his career, during the reigns of pharaohs Amasis II and Psamtik III, Udjahorresnet was a commander of ships (admiral), a physician and a priest of Neith in Sais.
[1]: 168–9 Nevertheless, his influence grew unexpectedly under the reign of the foreign kings, Cambyses and his successor Darius I: Udjahorresnet apparently became a sort of collaborationist for the Persians, managing to enter in the royal court as chancellor and chief physician.
[2] Acculturated by Udjahorresnet, the pharaoh paid homage to the goddess Neith at Sais, not before having driven out many Persian squatters who had settled within the temple; Udjahorresnet himself composed Cambyses' pharaonic titulary, calling him the Horus Smatawy (”He who unifies the Two Lands”) and the King of Upper and Lower Egypt Mesutire (“Offspring of Ra”).
In fact, archaeological evidences suggest Udjahorresnet was venerated after his death for some time by at least a part of the Egyptian populace.