Introduction: The optimal treatment strategy for the proximal humeral fracture (PHF) remains controversial. The debate is centered around the correct treatment strategy in the elderly patient population. The present study investigated whether age predicts the functional outcome of locking plate osteosynthesis for this fracture entity. Methods: A consecutive series of patients with surgically treated displaced PHF between 01/2017 and 01/2018 was retrospectively analyzed. Patients were treated by locking plate osteosynthesis. The cohort was divided into two groups: Group 1 (≥65 years) and Group 2 (<65 years). At the follow-up examination, the SSV, CMS, ASES, and Oxford Shoulder Score (OS), as well as a radiological follow-up, was obtained. The quality of fracture reduction is evaluated according to Schnetzke et al. Results: Of the 95 patients, 79 were followed up (83.1%). Group 1 consists of 42 patients (age range: 65–89 years, FU: 25 months) and Group 2 of 37 patients (28–64 years, FU: 24 months). The clinical results showed no significant differences between both groups: SSV 73.4 ± 23.4% (Group 1) vs. 80.5 ± 189% (Group 2). CMS: 79.4 ± 21 vs. 81.9 ± 16, ASES: 77.2 ± 20.4 vs. 77.5 ± 23.1, OS: 39.5 ± 9.1 vs. 40.8 ± 8.2; OS: 39.5 ± 9.1 vs. 40.8 ± 8.2. In the radiological follow-up, fractures healed in all cases. Furthermore, the quality of fracture reduction in both groups is comparable without significant differences. The revision rate was 9.5% in Group 1 vs. 16.2% in Group 2. Discussion: Both age groups show comparable functional outcomes and complication rates. Thus, the locking plate osteosynthesis can be used irrespective of patient age; the treatment decision should instead be based on fracture morphology and individual patient factors.