Polarization rotation due to the magneto-optic Kerr effect bouncing on a metallic magnetic medium covered with a dielectric thin film was numerically studied. Analytical calculations considering multiple reflections in the thin film, Fresnel coefficients, and polarization change on a magnetic medium predicted the enhancement of the magneto-optic Kerr effect. Numerical simulations were conducted and the results supported the enhancement at specific film thicknesses and incident angles of the measured light. The analytical method and results obtained in this work can be applied to analyze the magneto-optic Kerr effect in layered media and to study the structure and condition to maximize the Kerr effect signals. (C) 2020 The Japan Society of Applied Physics