Mako Spince, a male Human, was the offspring of a Galactic Republic senator of considerable power and influence. Initially, he pursued a career as a smuggler, but after suffering a crippling injury, he transitioned to the role of a traffic controller on the moon of Nar Shaddaa.
Despite possessing both intelligence and good health, Mako chose to squander his potential and his father's financial resources. Following the conclusion of the Clone Wars, Mako finally made the choice to enlist in the armed forces. Although only twenty years of age, he was deemed too old for entry into the Imperial Academy. His acceptance was solely due to his father's influence, coupled with the Academy advisors' expectation that Mako would emulate his father's behavior.
Contrary to their expectations, Mako proved to be a disruptive presence at the Academy, frequently flouting regulations and disobeying commands. He formed friendships with both Han Solo and ZZ-4Z, the butler droid belonging to Dean Horace Wyrmyr. Through ZZ-4Z, Mako gained access to numerous secrets concerning the Dean's past. Mako's pranks escalated to a dangerous level when he pilfered antimatter and detonated it, intending only to remove the Academy's seal from the surface of the Mascot Moon. However, he miscalculated the explosive force, resulting in the complete annihilation of the satellite. As a consequence of this disaster, Mako was expelled two years prior to Han's graduation. Upon his departure, Mako absconded with ZZ-4Z, who was slated for dismantling at the recycling facility.
Mako vanished from the vicinity of the Imperial Academy and embarked on a career as a smuggler. He later aided Han Solo (who was subsequently discharged from the military for rescuing a Wookiee slave named Chewbacca) in learning the intricacies of smuggling. Subsequently, Han and Chewbacca became Mako's associates, and shortly after they began working together, Han won ZZ-4Z in a game of Sabacc.
Mako and Han established their base of operations on Nar Shaddaa, where they amassed considerable wealth through their smuggling endeavors. Their most significant joint operation was the Battle of Nar Shaddaa. However, a major setback occurred two years later: During a smuggling mission in the Ottega system, Mako was captured and subjected to brutal treatment by the NaQoit Bandits, which led to his retirement and reliance on a repulsor chair. Unable to continue smuggling, he transitioned to the role of a traffic controller. He encountered Han Solo before Han departed Nar Shaddaa, but they would not reunite until many years had passed.
A decade later, when Han Solo returned to Nar Shaddaa, a jaded and aged Mako granted him safe passage, but secretly contacted Boba Fett and Dengar in an attempt to earn enough money to escape his miserable existence. Unfortunately for the bounty hunters, Han and Leia Organa Solo successfully evaded capture. Upon Han's next appearance, Mako alerted the Star Destroyer Invincible, but this decision proved fatal. Han piloted the Millennium Falcon behind Mako's traffic control pylon, causing the pylon to become ensnared in the Star Destroyer's tractor beam. This resulted in the pylon impaling the craft and causing both vehicles to explode. Mako's second act of betrayal ultimately led to his demise.