Organic dyes, such as Brilliant Cresyl Blue (BCB), are among the most persistent and difficult-to-treat water pollutants, primarily originating from textile factories that discharge enormous quantities of polluted water daily. Treating these large volumes requires readily available and durable materials. Palm waste, and more specifically, date palm leaves (DPL), is one of the least utilized materials due to a lack of awareness about it. To gain deeper insights into the material's structural and chemical properties, the biosorbent was thoroughly characterized before and after adsorption using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The value of the elemental charge of the absorbent material was also determined, and it was found to be 7.34, which expresses the almost neutral nature of the material's surface. The adsorption process was systematically studied by evaluating the influence of key operating parameters, including adsorbent mass, solution pH, and contact time. These parameters were systematically investigated and optimized using the Box-Behnken Design (BBD) coupled with Response Surface Methodology (RSM). Numerical optimization via the desirability function identified the ideal conditions as an adsorbent mass of 0.079 g, a solution pH of 9.17, and a contact time of 42.01 minutes, yielding an impressive removal efficiency of 98.15%. Furthermore, the comparative evaluation of the modeling approaches revealed the superior predictive performance of the Artificial Neural Network (ANN) over the Response Surface Methodology (RSM). This was clearly demonstrated by the significantly lower error metrics obtained with the ANN model across all evaluated parameters. Specifically, the ANN yielded a mean squared error (MSE) of 0.4022 vs 4.8427 for RSM, a mean absolute error (MAE) of 0.1538 versus 1.5994, a mean absolute percentage error (MAPE) of 0.17% versus 2.32%, and a standard deviation of error (SDE) of 0.6342 vs 2.2683. These findings confirm the enhanced accuracy, consistency, and generalization capability of the ANN model for simulating the adsorption process, making it a more robust tool for predictive modeling and process optimization in dye-removal applications. The results underscore the effectiveness and sustainability of date palm leaves (DPL) as a promising biosorbent for eliminating Brilliant Cresyl Blue (BCB) from polluted water, thereby supporting its practical applicability in large-scale environmental remediation efforts.