Martok was born in a common family, members of which had served the Empire as footsoldiers for generations. He was the first to apply for officer training, a request which was summarily rejected due to his lowly birth. Martok persisted and eventually entered the officer corps through a battlefield commission; the initial rejection would haunt him his entire career and fuel a long-time grudge against the man who made the decision, Kor.
Martok would spend two years in a Dominion internment camp, having been abducted from Qo'nos and replaced by a Changeling infiltrator. During his imprisonment he was used as target practice for Jem'Hadar soldiers; repeated battles cost him his left eye. After his escape in 2373, he gradually returned to active military duty, first as liaison and then as captain of the IKS Rotarran.
Gowron, however, resented Martok's popularity with his troops and subjects. After personally assuming command of all Klingon frontline forces, he attempted to disgrace Martok by sending him on ever-more-disastrous suicide missions. Martok, concerned that Gowron was letting a personal vendetta cost the lives of Klingon soldiers, resented this behaviour but refused to take a stand against it out of loyalty. When Worf forced the issue and killed Gowron in a duel, Martok accepted the position of Chancellor, hoping to rout the corruption that had been plaguing the Empire.