Background: Psychological factors influence rehabilitation and return to sport following anterior cruciate ligament (ACL) injury, yet evidence in futsal players remains limited. Methods: A qualitative multiple-case study was conducted with eight federated futsal players (five women and three men) with confirmed ACL injuries and five physiotherapists experienced in ACL rehabilitation. Semi-structured interviews explored athletes’ experiences across injury, rehabilitation, and return to sport, while physiotherapist interviews provided a clinical and temporal framework. Data were analyzed using thematic analysis and cross-case comparison. Results: Seven themes were identified: (1) emotional impact at the time of injury, (2) psychological challenges during early rehabilitation, (3) psychological adaptation throughout rehabilitation, (4) factors influencing rehabilitation adaptation, (5) return to sport and psychological readiness, (6) role of physiotherapists and social support, and (7) perceived psychological needs during rehabilitation. Fear of reinjury, uncertainty, frustration, loss of independence, motivational fluctuations, and reduced confidence were prominent challenges. Progressive goal achievement, individualized rehabilitation, previous injury experience, and support from physiotherapists, family, and teammates facilitated recovery. Seven athletes considered structured psychological support potentially beneficial. Conclusions: ACL rehabilitation in futsal should be understood as an individualized, dynamic biopsychosocial process. Repeated psychological monitoring, progressive sport-specific exposure, and access to specialist support may promote a safer and more sustainable return to sport.