On the road, Navin came across his life-long companion, a dog far more intelligent than its owner (though named "Shithead" after some unfortunate miscommunication). Stumbling into St.Louis, Harry Hartounian (Jackie Mason), the owner of a gas station, gives Navin his first break by offering him a job. For Navin this is just great, since he can follow at least one of the principles given to him by his folks (the other two are somewhat less useful). Harry doesn't seem to mind that Navin is an idiot, just so long as he doesn't destroy the place (which he comes close to doing). Luck really smile on Navin the day that Stan Fox (Bill Macy) pulls into the station though, for he causes Navin to come up with probably the brightest idea of his life - an invention which will come to be known as the "Opti-grab" handle.
Unfortunately for Navin, his delight at getting his name in the phone book is somewhat soured by the Madman (M. Emmet Walsh) who picks his name at random. As the bullets start flying, Harry ducks for cover, Stan drives away happy and Navin is forced to take refuge in a travelling carnival. Installed as a guess-your-weight operator, love comes Navin's way in the raunchy form of stunt rider Patty Bernstein (Catlin Adams). Claimed as her man, Navin finally discovers what his "special purpose" is for - and Patty wants him to use it a lot! All that Navin requires now is more emotional complication, in the form of pretty Marie (Bernadette Peters), and he's not even a millionaire yet.
The film lead-role debut of Martin, The Jerk is a whole lot like Forrest Gump, except that it's less serious and sentimental. Navin is basically a simpleton, someone who views the world through uncynical eyes and lands on his feet most of the time. The rags-to-riches adventures of Navin are highly amusing in their own right, though it's Martin's ability to recite surreal dialogue with a child-like directness that provides the required spin. The other members of the cast are a great help though, with everyone from Navin's adopted family to the middle-aged women in Marie's beauty parlour reflecting Martin's comic antics appropriately.
However, The Jerk is weakened, as a movie, in two important ways. The first of these is that the founding premise is shallow, rendering the entire script somewhat superficial. The overall feel is of a number of connected set-ups rather than a coherent tale, which results in only sporadic laughs. The other problem is that Martin hasn't achieved the smoothness of his later roles yet, such that he seems to be trying too hard to be funny. Luckily he doesn't manage to kill the jokes, but it's occasionally a close call. The Jerk is still pretty funny though, with Martin acting uncouth and dropping non sequiturs with abandon, it's just not a masterpiece.