Complex sentence: Skelton was soon starring in comedy features as inept radio detective "The Fox", the first of which was "Whistling in the Dark" (1941) in which he began working with director S. Sylvan Simon, who would become his favorite director.
Split into simpler sentences: Skelton was soon starring in comedy features as "The Fox", and inept radio detective. The first of these was "Whistling in the Dark" (1941), in which he began working with director S. Sylvan Simon, who became his favorite director.