Mirror Universe: Imperial Starfleet: Making the Most of Your Opportunities: The Career of Captain James T. Kirk

A fine example of advancement in the Imperial Starfleet is Captain James T. Kirk, commander of the I.S.S. Enterprise. One of Captain Garth's early proteges, the young Lieutenant Kirk used his mentor's influence to arrange an assignment on board the I.S.S. Farragut in 2254, immediately following his graduation from Starfleet Academy.
Kirk served on board the Farragut for three years until 2257, when Captain Garrovick was killed by a mysterious "vampire cloud" creature near Tycho IV after Lieutenant Kirk "hesitated" to fire the ship's phasers against the creature. Kirk moved up in rank to Lieutenant Commander following the Tycho incident and arranged to be assigned to the I.S.S. Enterprise, under the command of Captain Christopher Pike, where he made the acquaintance of Lieutenant Spock, a junior science officer.
While on a landing party, Kirk discovered the Tantalus Field in the looted laboratory of a dying alien scientist. With this device at his command, Kirk began slowly and systematically working his way up the ladder of command on board the Enterprise. By 2262, he was first officer on board the ship and later that year he arranged for the "disappearance" of Captain Pike and assumed command of the Enterprise with Spock as his first officer. The ship departed on a five-year mission of exploration and conquest in 2264.
The early missions of the Enterprise proved both successful and profitable for Kirk and his crew. They raided into Romulan space, providing a necessary show of force against the Romulan Empire. In 2267 Kirk executed Chief of Security Ben Finney for plotting against him. Lt. (j.g.) Hikaru Sulu assumed Finney's rank and position.
Shortly after Finney's execution, Lt. Commander Spock seized control of the Enterprise and directed it on a course for the forbidden planet of Talos IV, after imprisoning Captain Kirk and Commodore Mendez of Starbase 11. This "mutiny" was actually a ruse by Spock and Kirk to allow the Enterprise to approach the planet and bombard it, in order to destroy the Talosians, whose power of mental illusion posed a threat to the Empire. For his actions, Spock was promoted to the rank of Commander and both men earned medals from the Empire.
Kirk ended the conflict between Emiar VII and Vendikar by bombarding both planets until they were forced to surrender to the Empire. He also dealt with threat to Imperial mine workers on Janus VI, killing the silicate creature stalking them, and seizing its eggs for study. He put down a minor Klingon incursion into the Organia system before the Klingons could land on the planet.
In 2267, Kirk destroyed an alien weapon of unknown origin by tricking Commodore Matthew Decker into flying his starship, the I.S.S. Constitution, directly into the weapon. Kirk also oversaw the conquest of Gamma Trianguli VI and Coridan as new subjects of the Empire.