An essential tool for assessing the viscoelastic characteristics and temperature transitions of polymer composites is dynamic mechanical analysis (DMA). This research looked at the influence of process factors on the flexural and DMA properties of the coir fiber composite. These variables were fiber laying, length of the fiber, fiber volume percentage, and fiber surface treatment with alkali. According to Taguchi L18 design, needle-punched nonwoven was developed. Through this investigation, the optimized flexural strength of the sample was found as 52.812 MPa. According to DMA research, the greatest storage modulus, loss modulus, and loss factor were found to be 3.24 GPa, 0.508 GPa, and 0.164 Gpa at 26 °C and 55% RH. The best outcomes were obtained using cross-directional fiber laying, 6-cm fiber length, 40% fiber volume fraction, and 3% sodium hydroxide pretreatment. It was discovered by statistical analysis that the alkali pretreatment parameter had a significant relationship with both the flexural and dynamic mechanical characteristics of the composite.