Hercule is Clouseau's serious assistant, who suffers under Clouseau's eccentricity and arrogance. In the first film he has an assitant called Henri, but by "A Shot in the Dark" he has been replaced by Hercule. Hercule is also one of the characters interviewed by reporter Marie in "Trail of the Pink Panther". He is one of many characters played by Graham Stark.
In "A Shot in the Dark", Hercule assists Clouseau throughout the case. When Maria is under suspicion, because she was found with the murder weapon in her hand, next to the body of the victim who had allegedly assaulted her, Hercule concludes that she killed him, which angers Clouseau, who has feelings for her. At the end of the film Clouseau is ready to prove his theory, which is in fact correct, and assembles the household, instructing Hercule to turn out the lights at a certain point. Naturally everything dissolves into chaos.
In "Trail of the Pink Panther" Hercule is enjoying retirement on his boat, and does an inerview about his former boss for Marie.