Transition metal dichalcogenides (TMDs) have emerged as cost-effective and efficient alternatives to conventional noble metal catalysts, showing remarkable potential for the hydrogen evolution reaction (HER). Nevertheless, achieving superior performance in acidic media remains a significant challenge. In this study, we report the synthesis of tungsten-doped molybdenum sulfo-selenide (Mo_1-xW_xSSe) via a simple hydrothermal method, yielding a non-noble, highly active, and durable HER electrocatalyst. In 0.5M H₂SO₄, Mo_0.5W_0.5SSe exhibited an exceptionally low overpotential of 228 mV at 10 mA cm^-2 and a Tafel slope of 118.17 mV dec^-1, following the Volmer–Heyrovsky mechanism. The outstanding HER activity is attributed to the synergistic interaction between Mo and W, resulting in a higher density of active sites, improved electron transfer, enhanced exposure of basal planes, increased conductivity, and reduced charge transfer resistance. Moreover, the catalyst demonstrated excellent durability, maintaining stable performance for over 14 hours of continuous operation. Additionally, Mo_0.5W_0.5SSe exhibits high double-layer capacitance (C_dl) and an electrochemically active surface area (ECSA), along with low charge transfer resistance (R_CT) compared to its counterparts. This work provides valuable insights into designing advanced TMD-based electrocatalysts for efficient and durable hydrogen generation in acidic media, thereby supporting Sustainable Development Goals 7 (Affordable and Clean Energy) and 13 (Climate Action) by enabling clean energy production and reducing carbon emissions.