The city of Kolkata has always figured prominently in his work. His themes come from personal interactions with its urban milieu - its sickness and sordidness, its violence and vulnerability, and all that compounds its existential agony. In the 1960s and 1970s, his work was influenced by turbulence and political violence of Kolkata.

Subhaprasanna has depicted varying moods of the city and its people, its places, and all its facets that make the city distinctive. He states, "There isn't another city like Kolkata anywhere in the world. In the heart of it, I find innumerable themes, subjects." He does not merely portray reality as 'matter of fact' and his presentation of reality often has dream-like elements in it. In terms of technique, Subhaprasanna boasts a precise, finely executed style that yields an unmistakable visual intensity. He works comfortably in an assortment of media, including oil on canvas, charcoal, and mixed media.

Explaining his thought-process and philosophy as a painter, he notes: "What every creator wishes to achieve is a universal appeal. There should be no language problem while judging the merits of a painting. One should go beyond themes, beyond words. There can be no clear cut definition for feelings, nor should you wish to seek any logical explanation."

Subhaprasanna's series of paintings, Icons and Illusions, marked a creative breakthrough for the artist in a number of ways. Whereas he had been known in the past as an urban artist with subject matter that reflected the byways, alleyways, birds, and people of his native Kolkata, in this series he relished more in divinities and flowers. The iconic figures of Krishna, Radha, and Ganesha that found lyrical expression in the Icons series are modern representations and sophisticated idealizations of the same images in the popular media.