This study explores the application of lateral waterjet laser cutting in the fabrication of brush seals for gas turbine engines, with the aim of optimizing process parameters to enhance cutting quality. Experimental and numerical analyses were conducted to assess the effects of laser power, scanning speed, waterjet velocity, and waterjet standoff distance on key outcomes, such as kerf width, heat-affected zone, and recast layer thickness. The findings indicate that a laser power of 500 W, scanning speed of 15 mm/s, waterjet velocity up to 10 m/s, and waterjet standoff distance of 1 mm are optimal for reducing thermal damage and achieving precise kerfs. Furthermore, numerical simulations highlight the significance of controlled molten flow in realizing these optimal results, providing a comprehensive understanding of the cutting mechanism. These findings position lateral waterjet laser cutting as a better technique for brush seal manufacturing, offering significant improvements over conventional methods.