The poem is narrated by Fra Lippo Lippi, a Florentine painter and friar of the fifteenth century. Lippi is stopped by watchmen just as he drunkenly leaves a bordello. They tell him that he ought not be on the streets at night and are surprised to find a friar in such a state. Drunkenly, Lippi tells them his story. He was orphaned and taken to a monastery where the monks set him to work painting on the walls of the church.

The friars are amazed by his skill, but insist that he remove his work for it is a representation of bodies, not of souls. It does not teach a moral lesson, either. So Lippi sarcastically paints a gruesome picture of the martyred Saint Lawrence. When a group of nuns enlist his help, he paints a cloudy collection of saints surrounding Mary but in the corner is an image of himself. He enters their presence in all his fleshy glory.