Throughout the first film, Professor Sherman Klump is portrayed as highly intelligent and generally respected by his students, as well as being a fundamentally friendly man, but has occasional clumsy accidents due to his obesity.

Having recently fallen in love with grad student and chemistry teacher Carla Purty (Jada Pinkett Smith), Klump uses his latest discovery, a weight-loss serum that rewrites the subject's genes, to lose weight in order to spend time with her.

When Klump's student and assistant Jason learns what has happened, he realizes that Buddy is gaining increasingly greater freedom from the professor's influence.

Describing him as a "peculiarly American stock character" similar to Ned Brainard in The Absent-Minded Professor, Gunden states that he represents a man who has put all his energy into harnessing his intellectual side, but had none left for socializing, sexuality or common sense.

Through the alter-ego of Buddy Love, Jerry Lewis also tried to demonstrate his ability to play different roles after being typecast numerous times as the "kid", a crazy man-child.

[3] In Comedy Is a Man in Trouble, Alan S. Dale states that Kelp is Jerry Lewis acting out "the two poles of his personality", the innocent one that made him a star, and a callous, successful persona he had kept well-hidden.

Dale describes Buddy Love as representing Lewis' true personality as a "bastard-mogul", comparing him to Charlie Chaplin's "brilliantly heartless" Tramp persona, or the Great Dictator but "even more inappropriately egomaniacal".