This study aims to analyze and theorize the generative structure and transformation-transition mechanism of "disability habitus," which has an absolute influence on adult learners with disabilities who belong to the most marginalized and at-risk group in the context of lifelong learning. These learners repeatedly fail to enter and adapt to the lifelong education field after completing formal schooling. Using a grounded theory approach, the study examines 19 research participants (from October 2018 to August 2024) to visualize the relationships, experiences, and problematic contexts in which the identity of ‘disability’—embodied in individuals throughout their life course—is formed, transformed, and distorted. The study results indicate that the initial formation and structure of disability habitus are shaped through the family field (Champ), establishing a dual causal condition of: (1) the identification with "normality" and (2) the identification with "abnormality." This duality serves as the first moment of structuralization, where individuals are positioned—either positively or negatively—at the boundary between normality and abnormality. Subsequently, the school environment functions as a powerful social space that refracts and perpetuates the pre-structured disability habitus in a specific direction. As a result, the research participants experienced a central phenomenon that can be described as the transformation of disability habitus and the embodiment of a socially conditioned body. Within this dynamic, two distinct types of social relationships exert a crucial influence on the process. The first is the "disability habitus" shaped within the teacher-student relationship as a [contextual condition]. This structure molded: (1) tacit acceptance and neglect, (2) explicit vs. implicit discrimination and bias, (3) liminal experiences of exclusion and isolation, and (4) harsh discipline and the stigma effect. The second factor is the [action and interaction strategy], which is shaped through social relationships with peer groups (non-disabled students) and has the strongest influence on the internalization of the "socialized body" beyond the "physical disability." This process is reinforced through three stages: (1) the creation of a collective atmosphere of hostility, (2) the transmission effect of verbal violence, and (3) the normalization of physical violence. As a [consequence], the transition and transformation of disability habitus in adulthood were reinforced and sustained by the following factors: (1) low self-esteem and avoidance of relationships, (2) persistent psychological trauma, (3) the embodiment of "numbing the senses" and "self-suggestion," and (4) repetition of regret and self-reproach, which continued and intensified throughout the life course. Based on this, the [selective coding] stage derived core categories and proposed a grounded theory, which was summarized into two key aspects: (1) failure in forming relationships with others—an experience of "separation" from society, and (2) failure in forming a relationship with oneself—"distortion" and "twisting" of the self. Finally, the study deepened the discussion by linking its findings to Bourdieu’s key theoretical arguments.