Background Complex femoral fractures remain a major orthopedic challenge in high-energy trauma, often requiring individualized management strategies. In middle-income countries such as Morocco, the decision between external fixation (ExFix) and internal fixation (InFix) depends on patient condition, soft-tissue status, and available surgical resources. This multicenter Moroccan study compared radiological healing, functional recovery, and complication profiles between ExFix and InFix in complex femoral fractures. Methods A prospective multicenter cohort study was conducted from January 2019 to December 2024 across CHU Ibn Sina (Rabat), CHU Mohammed VI (Marrakech), and Hôpital Militaire d’Instruction Mohammed V (Rabat). A total of 120 adult patients with AO/OTA 32-B/C femoral fractures were enrolled—60 treated with definitive external fixation and 60 with internal fixation (reamed intramedullary nail or locking compression plate). Radiological union, functional outcomes (LEFS, HHS), and complications were compared at 3, 6, and 12 months. Kaplan–Meier survival analysis evaluated time to union and functional recovery (LEFS ≥ 70). Predictors of delayed union were analyzed using Cox regression modeling. Results The mean age of patients was 37.4 ± 11.2 years with 75% males; road traffic collisions were the main injury mechanism (82%). Union was achieved in 92.5% overall, with faster healing in InFix (mean 24.8 ± 6.3 weeks) compared with ExFix (29.4 ± 8.0 weeks, p = 0.006). At 12 months, InFix patients had significantly higher functional outcomes (LEFS: 78.9 ± 8.2 vs. 67.4 ± 9.6; HHS: 87.2 ± 7.1 vs. 79.1 ± 8.0; p < 0.001). Kaplan–Meier analysis showed earlier union and recovery in InFix (log-rank p = 0.032 and 0.025, respectively). Complications were more frequent in ExFix (33.3% vs. 20.0%), particularly pin-tract infections (16.7%) and malalignment (10%). Cox regression identified open fracture (HR = 2.42, p = 0.004), definitive ExFix (HR = 1.89, p = 0.021), and ISS ≥ 16 (HR = 1.56, p = 0.048) as independent predictors of delayed union. Conclusions In Moroccan tertiary trauma centers, both fixation methods achieve satisfactory union, but internal fixation provides faster bone healing, superior functional recovery, and lower complication rates. External fixation remains indispensable for damage control orthopedics, especially in polytrauma and open fractures. These results support the development of context-sensitive fixation algorithms for North African trauma systems emphasizing early stabilization, staged conversion, and structured rehabilitation.