Atsuko Urameshi is the mother of the series' protagonist, Yusuke Urameshi. She is a young woman who became a parent at the age of fourteen or fifteen, raising Yusuke as a single mother. Throughout much of the story, she is twenty-nine years old. Atsuko is frequently depicted as an alcoholic, often shown drunk, hungover, or passed out, which contributes to her initially appearing neglectful and irresponsible. She was even seen leaving her son's body surrounded by trash after his death, which highlights her low point as a parent.

Despite her seemingly careless exterior, Atsuko genuinely loves her son and wants him to have a better life than she did. This deep-seated care is not fully understood by Yusuke until he witnesses her weeping in grief at his wake after his untimely death. This moment serves as a turning point, revealing the profound sorrow beneath her detached demeanor. Following Yusuke's revival, she becomes more protective and involved in his life, enforcing his school attendance and being terrified by nightmares of losing him again.

Atsuko's role in the story is primarily as a supporting character in Yusuke's personal life. Her presence is more prominent in the manga than in the anime adaptation. In the manga, she accompanies Keiko Yukimura, Shizuru Kuwabara, and Botan to the Dark Tournament, a storyline from which she is notably absent in the anime. She also has a role in the Chapter Black saga in the manga, a part that was largely given to Shizuru Kuwabara in the anime version. In the OVA titled All or Nothing, she pragmatically aids Yusuke in his spirit world mission by knocking him unconscious with a baseball bat so his spirit could leave his body.

Her key relationships are centered on her son, Yusuke, with whom she shares a bickering but affectionate bond, and his childhood friend Keiko Yukimura, whom she reassures about Yusuke's well-being. The manga also hints at her having shadowy connections to the yakuza or other underworld figures, which she uses to coerce the school chairman into readmitting Yusuke and to extort money from local pimps.

Over the course of the narrative, Atsuko develops from a seemingly hopeless and neglectful alcoholic into a more responsible and actively caring mother, though she never loses her rough edge. Her character arc shows resilience and a pragmatic, if unconventional, form of maternal care. In terms of abilities, in the manga storyline, Atsuko is spiritually aware, possessing the ability to see and sense demons. She also demonstrates unexpected combat prowess, seen when she defeats a demon security guard alongside Shizuru Kuwabara. Her fighting spirit is also implied when she watches Yusuke fight and comments that it reminds her of her own "salad days," or youth. At the end of the manga, she is seen attending a horse race, remaining a steady, if unsentimental, presence in her son's life.