FeSi films have been rf sputtered on glass, fused silica, and Si substrates. Sputter targets of 2 and 7 wt% Si were used, and the film thickness was varied between 0.1 and 4 &mgr;m. Several films, especially those on glass in the 0.5‐&mgr;m‐thickness range, showed a characteristic roughly rectangular domain structure. The films were isotropic. The structure has been analyzed with the longitudinal magneto‐optic Kerr effect by rotating either the film or the demagnetizing field in the film plane. The magnetization made an angle of about 18° with the longer walls. A new magnetization process, ``wall rotation'', could be observed.