This paper presents a method to reduce surface variation in face milling processes based on high-definition metrology (HDM) measurements. Our previous research has found and established the relations between surface variation patterns, cutting forces, and process variables. Based on the findings, this paper compares potential machining methods and finds that the approaches of varying feed rate and lateral cutter path planning are most feasible for surface variation control. By combining the two approaches, an algorithm is developed to reduce cutting force variation along the feed direction and circumferential direction, respectively, thereby reducing the surface variation. The varying feed method can effectively eliminate the surface variation along the feed direction, while the optimal cutter path approach balances the cutting loads on the cutter and contributes to reducing cutting force variation along feed direction. Case studies were conducted based on a cutting experiment to demonstrate that the proposed method can improve the surface flatness by 25%. The cutter path adjustment algorithm was also implemented in an automotive engine plant leading to 15–25% improvement in surface flatness.