The film focuses on prickly genius Lynn Belvedere (Clifton Webb) who enrolls in a major university with the intention of obtaining a four-year degree in only one year.

Lynn Belvedere, though the successful author of a scandalous, best-selling book titled Hummingbird Hill (as described in Sitting Pretty), has not benefited financially, as he has had to fight many libel suits as a result.

Belvedere intends to complete the four-year program in a single year, even though he has no formal education.

He is assigned to share a dorm room with freshman Corny Whittaker and bossy sophomore Avery Brubaker.

Belvedere is punished for shaving during "Whisker Week": he has to wear a fake beard until further notice.

Instead, Belvedere advises Ellen not to publish pure gossip in future and not to submit another, longer article to Look Magazine.

Two patrol officers saw him and find him in her apartment and arrest him, believing he is a Peeping Tom when Ellen lies, claiming not to know Mr. Belvedere.