This study explored using cellulosic plant fibers as composite-reinforcing materials for structural applications. Specifically, a green composite material was created using Agave cantala fiber (ACF) and an epoxy matrix with weight fractions ranging from 30% to 60%. The laminates were fabricated using a compression molding technique, which involved alternating layers of resin and fibers on a flat mold. The fibers were uniformly aligned, and the resin was layered over them. The mold was then covered with polyethylene film to ensure that voids were minimized, and the mold was compressed for 12 h at ambient temperature. Four different samples were created by varying the fiber and resin weight percentages, with ACF30 containing 30% fiber and 70% resin, ACF40 containing 40% fiber and 60% resin, ACF50 containing 50% fiber and 50% resin, and ACF60 containing 60% fiber and 40% resin. The resulting composites were characterized to investigate their mechanical properties and it was found that the 40% ACF laminates had the maximum tensile, flexural, and compressive moduli and strengths. Additionally, viscoelastic characteristics were evaluated, and the 40% ACF composite demonstrated the highest storage and loss moduli. Scanning electron microscopy was also used to interpret the interface between the fibers and the matrix at the fracture surfaces. These findings suggest that cellulosic plant fibers have the potential as reinforcement materials for creating high-performance composites.