Complex sentence: Leonard produced and was the production manager for many of the television shows produced for Screen Gems which included "The Adventures of Rin Tin Tin", "Circus Boy", "Naked City", and "Route 66".
Split into simpler sentences: Leonard produced and was the production manager for many television shows for Screen Gems. Some include "The Adventures of Rin Tin Tin", "Circus Boy", "Naked City", and "Route 66".