Background Young judo athletes show highly heterogeneous pre-competition psychological states, yet prior variable-centered research has assumed a uniform linear “support–anxiety” relationship that masks individual differences. Using latent profile analysis, this study aimed to identify subgroups jointly defined by perceived social support and competitive state anxiety, examine unadjusted between-profile differences in depression and mental toughness, and investigate covariate-adjusted correlates of profile membership. Methods A cross-sectional design was employed. A total of 222 young Chinese judo athletes were assessed using the Multidimensional Scale of Perceived Social Support (MSPSS), the Competitive State Anxiety Inventory-2 (CSAI-2), the Center for Epidemiologic Studies Depression Scale (CES-D), and the Sports Mental Toughness Questionnaire (SMTQ). Standardized perceived social support and competitive state anxiety served as the indicator variables for latent profile analysis (LPA); the retained profile solution was selected by jointly considering the AIC, BIC, SABIC, entropy, and class proportions. Binary logistic regression was used to examine the covariate-adjusted associations of mental toughness and habitual stress with profile membership while controlling for age, sex, and history of acute sports injury. Independent-samples t -tests were used to examine unadjusted between-profile differences in depression and mental toughness. Results A two-profile solution was retained after jointly considering information criteria, profile size, classification accuracy, parsimony, and substantive interpretability (entropy = 0.679). The Resource-Deprived profile comprised 36.5% of the sample, whereas the Supported–Vigilant profile comprised 63.5%. The Supported–Vigilant profile reported lower depression ( p < 0.001) and higher mental toughness ( p = 0.035). Mental toughness was associated with higher adjusted odds of Supported–Vigilant profile membership (OR = 1.34, 95% CI [1.01, 1.80], p = 0.047). Conclusion The retained profiles were distinguished primarily by jointly lower versus jointly higher levels of perceived social support and composite competitive state anxiety. In the Supported–Vigilant profile, higher composite competitive state anxiety coexisted with lower depression and higher mental toughness; however, the present findings do not establish that anxiety was facilitative or that social support buffered its effects. These findings suggest that pre-competition psychological work should assess anxiety intensity together with perceived support and broader psychological adjustment, rather than uniformly pursuing anxiety reduction, while giving particular attention to resource-deprived athletes.