Hugo is an orphaned teenager living in the industrial sprawl of the Scrapyard, a place from which he dreams of escaping to the floating city of Zalem. He belongs to the low social class of his world and is driven by an intense, almost obsessive ambition to reach the wealthy sky city, believing that life there is the only path to a better existence. This all-consuming goal shapes his actions and moral choices, leading him to become involved in criminal activities. Unbeknownst to Alita when they first meet, Hugo works with a broker named Vector, participating in a scheme to steal the spinal columns of cyborgs to sell on the black market to fund his dream.

Personality-wise, Hugo is stubborn and resolute when it comes to his aspirations, but he also possesses an honest streak, confessing to his crimes rather than deflecting blame. Some perspectives describe him as a morally ambiguous character, an opportunist whose selfish actions are rationalized by his grand goal of reaching Zalem. He is not inherently malicious, but his desperation makes him willing to harm others, preying on cyborgs to dismantle them for profit, even if he remains willfully ignorant of the full consequences of his actions. Despite these flaws, he shows genuine kindness to Alita, and his dream is rooted in a tragic personal history involving his brother.

In the story, Hugo serves as Alita's first love and a major catalyst for her emotional development. He enters her life when she is still discovering her own identity, and she becomes infatuated with him, projecting her hopes and desires onto their relationship. Initially, Hugo is somewhat oblivious to her romantic interest, focused solely on his plan, but he eventually comes to reciprocate her feelings. Their relationship is central to the narrative, as Alita goes to great lengths to help him, even offering him her own hard-earned money to achieve his goal and fighting to protect him from his enemies. However, her trust is shattered when she discovers his secret life as a criminal, though she ultimately forgives him after understanding his motivations. Her relationship with her father figure, Dr. Ido, is strained as a result of her devotion to Hugo, as she defies Ido's protective warnings about the boy.

Hugo's character arc is one of tragic realization and failure. After Alita saves his life following a brutal attack by another hunter-warrior, his head is transplanted onto a makeshift cyborg body. Upon learning that Vector's promise of passage to Zalem was a lie and that no one from the surface may ever ascend to the floating city, Hugo becomes unhinged with despair. In a desperate, final act, he attempts to climb the massive service tubes leading up to Zalem. Despite Alita's pleas for him to return, defense mechanisms on the tube activate and tear his new cyborg body apart. His arm snaps off in Alita's grasp, and he falls to his death, his last words expressing gratitude for having met her. This event devastates Alita and profoundly changes her, driving her to abandon her former life and seek a new purpose in the brutal sport of Motorball.

As a character, Hugo possesses no special combat abilities, functioning as a regular human within the world of enhanced cyborgs. His significance lies not in physical prowess but in his emotional impact on the protagonist. He represents Alita's introduction to romantic love, heartbreak, and the painful understanding that some people are destroyed by their own impossible dreams.