The role earned him considerable critical attention, including interest from MGM to put him under contract specifically for the role of Dr. James Kildare in an upcoming film series. Ayres played the role in nine films from 1938 to 1942 (and again in a 1950s radio series) while also appearing in light comedies for MGM, including "Spring Madness" and "Rich Man, Poor Girl" (both 1938), "The Ice Follies of 1939" (1939), and "Fingers at the Window" (1942). His final film as Dr. Kildare, "Born to Be Bad", was re-edited after he was drafted and declared himself a conscientious objector in March 1942.