Jackson Alan Bretta was born in an Alliance mining camp on Antares IX, nine months after his father brutally raped his mother. Jack never knew his father, as Johnathan Bretta was immediately executed by his Alliance slave masters following the assault. Alexa Sanchez hated the child that resulted from the rape and tried to kill him after birth but the slave masters forced her to nurse and raise the child under constant supervision, in hopes of using him as a future slave.

At age five Jack was pressed into harsh back-breaking labor and at age seven forced to watch his mother die a gruesome death, after Alexa killed one of the Cardassian slave masters in order to avoid becoming the Cardassian's comfort woman. Jack was unfazed by the death of his abusive mother, in fact laughing at her while the Cardassians savagely beat her. Once Jack reached puberty, the Klingons placed him into mortal combat against his fellow teenage slaves, both Terran and alien. Jack learned all the necessary skills of combat and became a professional, earning great respect among the Klingons. At age twenty, he was tranferred to the Cardassian mining station Terok Nor where he spent the next two years processing uridium ore until the slave revolt.

Jack's service for the Empire began when he took part in the slave rebellion on Terok Nor, one of Jack's glorious moments as he killed Alliance oppressors by the dozens. Three years later, Jack served as Assault Force leader aboard the newly built ISS Defiant and took part in the Terran Resistance's successful defence of Terok Nor, by driving back the Alliance forces led by Regent Worf. It was in this battle that Jack earned favor with Captain Miles "Smiley" O'Brien.

After the rise of the Imperial Union of Planets, Jack transferred to the ISS Scorpion under the command of Captain Fedmahn Kassad, with whom he was often at odds, as Jack viewed Kassad to be a weak-minded fool. In 2380, the Scorpion crossed over to the mirror universe on a mission to steal starship and weapons designs from the Federation for the Empire. During Jack's infiltration of the Federation starship USS Odyssey, Kassad attempted to strand Bretta in the false universe by alerting the Odyssey's crew to his presence and allowing him to be captured, seeing this as the perfect means of eliminating a threat to his life. Jack escaped confinement and returned to the Scorpion without the data he was sent to retrieve. Kassad, enraged at his failed attempt to rid himself of Bretta, ordered his sadistic Chief Medical Officer, Ariana "Dr. Death" Spinelli, to torture Bretta as punishment for failure to complete the mission. Jack was mutilated and left with various scars along much as his body after being sliced by a scalpel and crudely healed with a low-powered dermal regenerator. Jack learned the truth of his failure shortly following his torture and vowed to get revenge on Kassad. In 2384 he finally got it when he ambushed Kassad in a corridor and splattered his brains across the hall with an old-style 12-gauge shotgun to the head... right after he blew off both of Kassad's kneecaps.

Jack left the Scorpion shortly afterwards and spent the rest of the year doing covert military operations for the Empire until he was recalled to Terok Nor, before being posted to the highly advanced ISS Arcadia.