Aim: This study aims to examine self-inflicted tattooing behaviors performed by individuals using primitive tools such as sewing needles and to evaluate the sociodemographic, psychological, and criminal characteristics associated with this group. Methods: The study was conducted in 2020 with 200 tattooed individuals whose criminal responsibility was under forensic evaluation. Participants who exhibited self-inflicted tattooing behavior (n = 66) and those who did not (n = 134) were assessed through semi-structured interviews and psychometric tests. The applied scales included the Barratt Impulsiveness Scale-11, Levenson Self-Report Psychopathy Scale (LRSP), Body Image Scale, Rosenberg Self-Esteem Scale, and Hamilton Anxiety Scale (HAM-A). Results: Participants in the self-inflicted tattoo group were more likely to have lower educational attainment, irregular or no work history, institutional upbringing, and earlier exposure to crime. Psychometric evaluations revealed significantly higher levels of impulsivity, psychopathic tendencies, anxiety, negative body image, and lower self-esteem in this group. All individuals with self-inflicted tattoos reported at least one form of self-harming behavior. Conclusions: Self-inflicted tattooing is not merely an aesthetic choice but may reflect deeper psychosocial problems and criminal risk factors. These tattoos can provide valuable clues regarding an individual’s psychological profile and life history during forensic assessments. Thus, systematic inclusion of self-inflicted tattoo evaluation in medico-legal examinations is recommended.