In this study, six chip-breaker geometries, including three finishing and three roughing designs with different groove widths, groove depths, effective rake angles, and chip-guiding geometries, were experimentally investigated. The effects of these chip-breaker geometries on cutting force, cutting temperature, material removal rate (MRR), and surface roughness were evaluated. The results showed that increasing the spindle speed from 500 to 1000 rpm reduced the cutting force by approximately 15–30% for the finishing chip breakers and 10–20% for the roughing chip breakers. Moreover, increasing the feed rate from 0.08 to 0.16 mm/rev increased the cutting force by 30–45% in finishing and 40–60% in roughing operations. The cutting temperature was lower for the finishing chip breakers than for the other geometries, while the temperature difference between the lowest and highest feed rates ranged from 15–25% in finishing and 30–45% in roughing operations. Surface roughness increased by 40–60% in finishing and 30–50% in roughing with increasing feed rate, whereas the optimized finishing chip breakers produced up to 25–35% lower surface roughness than the non-optimized geometries. The results demonstrate that selecting an appropriate chip-breaker geometry according to the machining operation plays a decisive role in reducing cutting force and temperature while improving surface quality and machining productivity of AISI 304 stainless steel.