Lewis--who also directs--plays Professor Julius Kelp, a bizarrely nerdy-but-stupid chemistry professor. He has a knack for conducting dangerous, unauthorized experiments in the presence of students. At the beginning of the film, he blows up his classroom yet again. On a later day, a football student who was denied permission to leave class early for football practice responds by stuffing Kelp into a shelf. Beautiful student Stella Purdy (Stella Stevens) feels sorry for Kelp and helps him unstuff himself. Stevens skillfully has the slightest gleam in her eye while doing this so that we can tell that Purdy has an attraction to the strange-looking professor.
Spurred on by the incident--with both the physical abuse and the physical attraction as motivators, Kelp decides to give himself a make over. He first tries his luck at the local gym. When that doesn't work out so well he puts his chemistry knowledge to use and hits upon a potion that produces a Jekyll & Hyde transformation. The Nutty Professor has Kelp trying to balance the two personalities, with the expected calamitous but humorous results.
Although Lewis' Hyde character, "Buddy Love", is often said to be a skewering of his early comedy partner and pal Dean Martin, Lewis claims this wasn't the case. Both the nerd and the debonair but sublimely obnoxious hipster were supposedly amalgamations of different people Lewis had encountered over the years. Still, the similarities to Martin are difficult to deny; perhaps the character was partially a subconscious parody of Martin.
In any event, Love is entertaining to watch--he's something like a glossy trainwreck. Or maybe like a suave Satan in a silk suit. Lewis makes both characters complex in their differences from their respective stereotypes. Kelp is the stereotypical "absent-minded professor", only the absent-minded professor is usually a wiz at his academic subject. Lewis paints Kelp as primarily a wiz at being a slightly sympathetic dork, where his cockeyed chemistry successes are more accidental. Love is the stereotypical overbearing but attractive-to-the-women brute, yet Lewis is quick to imbue him with an odd combination of pathos and flair, so that Love ends up being both more fragile and more talented/intelligent.
Some of the material employing both characters is quite funny, but Lewis dwells on humor no more than a whole gamut of modes and emotions, from fairly serious horror material during the slightly overlong initial Jekyll/Hyde transformation to poignantly sad, touching scenes showing the crack in the Love armor. To an extent, the Jekyll/Hyde theme permeates the film in its shifting tones.
One of those modes that works surprisingly well is the musical material. Lewis hired the superb Les Brown and other great jazz musicians to provide songs. Les Brown's "Band of Renown" even makes an on screen appearance, performing a couple songs at a college dance. Lewis isn't the greatest singer, but he does a passable job with an alluring rendition of "That Old Black Magic". There's also a great version of "Stella by Starlight" in the background of a couple scenes.
The performances are quite good. Both Stevens and Del Moore, as Dr. Hamius R. Warfield, the college dean, easily hold their own next to Lewis, who does a remarkable job with the transformations. He's helped a lot by W. Wallace Kelley's cinematography. Kelley had a more than respectable, varied background, including camera experience on a couple Alfred Hitchcock films--To Catch A Thief (1955) and Vertigo (1958)--and Cecil B. DeMille's The Ten Commandments (1956). Kelley uses very subtle angle changes to make Kelp seem small and insignificant (aided by Lewis' physical contortions) while making Love seem like a big, macho guy.
The production design is also gorgeous. Lewis directs his crew to fill the film with bold, unusual color combinations--most overtly in the rainbow-colored paints on the lab floor during the first Jekyll/Hyde transformation, the nice overlaying of purples and reds in The Purple Pit club, and the great, unusual coordinations of Love's suits.
Whether you find The Nutty Professor hilarious or not, it has certainly been influential. Lewis considers this his best film. The American Film Institute placed The Nutty Professor at number ninety-nine on its list of the "100 Funniest American Films" ("100 Years/100 Laughs"). Both Adam Sandler and Jim Carrey have obviously been influenced by this film, as they have been by Lewis in general. And Andy Kaufman's disparate characters Latka Gravas (from 1978-1983's "Taxi") and Tony Clifton (a regular part of his live act) are direct parallels to Kelp and Love, even if Kaufman had other influences for those characters, as well.
The Nutty Professor is also a "message" film. The dual "morals" of the story, in addition to the less conspicuous subtexts dealing with personal identity, are to not be afraid to be your true self and to accept others for their true selves--to look deeper than the surface level.
Given such wide-ranging moods and aims, it's probably best to watch the film without genre expectations. That's not likely to make those averse to Lewis' shtick enjoy it any more, but for everyone else, The Nutty Professor is worth a look. It will surprise you with its diversity.