In this study, we synthesize highly crystalline cobalt NWs in the form of powder and ordered nanomagnets using a solvothermal technique. We study morphological, structural, and magnetic properties of the resulting NWs using field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and first-order reversal curves. The nanomagnetic properties are investigated and compared between different magnetic field angles by extracting several parameters such as major, irreversible, and reversible hysteresis curves. Our results indicate that the coercive field of the major hysteresis curve follows the product of irreversible coercivity and irreversible fraction as a function of the field angle. This enables us to control the nanomagnetic properties of ordered cobalt NWs with a high energy product (BH_max = 16 MGOe) by subtle changes in their irreversible magnetization.