Coal-based thermal power plants in India produce about 271 million tons of Class-F fly ash (FA) yearly, causing severe disposal and environmental issues. The bulk utilization of virgin fly ash in geotechnical structures is limited due to its little self-hardening and low pozzolanic behavior. The current study stabilized fly ash with different cement content (3, 6, 9, and 12%) and polyester fiber (0.25, 0.5, 0.75, and 1.00%). For these mix proportions, unconfined compressive strength and split tensile strength were determined under light and heavy compactions. The durability of the fiber-reinforced fly ash–cement mixes was examined under wetting–drying (W-D) and freezing–thawing (F-T) cycles. The test results show that the strength properties of the compacted fly ash substantially improved with the addition of cement due to the formation of reaction products. The strength properties of the fly ash–cement mixes were further enhanced with the inclusion of fiber. The fiber-reinforced material has better durability against W-D and F-T cycles. In addition, the strength properties and durability of the stabilized fly ash are enhanced with an increase in the compaction energy due to a better interlocking mechanism.