Complex sentence: The former was made into a biographical comedy film in 1997 that had Stern and his radio show staff play themselves; it topped the US box office chart and grossed $41.2 million domestically.
Split into simpler sentences: The former was made into a biographical comedy film in 1997, in which Stern and his radio show staff play themselves. It topped the US box office chart and grossed $41.2 million domestically.