Driven exercise is a transdiagnostic maladaptive behavior, especially common in eating disorders (EDs); however, its maintenance mechanisms remain poorly understood. To address this gap, we examined the applicability of previously empirically derived and validated reinforcement-function models in explaining driven-exercise maintenance in studies varying across developmental stages and clinical presentations (Study 1: N = 279 adolescents/adults oversampled for EDs; Study 2: N = 118 adolescent/adult inpatients with severe EDs; Study 3: N = 52 adults oversampled for athletes and/or EDs). Results supported the utility of a four-function model (automatic positive reinforcement [APR]/automatic negative reinforcement [ANR; increase positive/decrease negative affect], social positive reinforcement [SPR]/social negative reinforcement [SNR; engage in/avoid interpersonal situations]) in explaining driven exercise. APR was most frequently endorsed, followed by ANR, SNR, and SPR in all studies. APR correlated with last-month driven-exercise episodes across studies; associations between other functions and ED psychopathology varied between studies. Furthermore, results suggested a separate control function could be considered in samples with more severe EDs.