José Leonilson's work is mainly concentrated in the last ten years of his life, during which he created a substantial and consistent body of work. His creations span across painting, drawing, illustration, embroidery, installation, and sculpture. In an exercise of synthesis, with each new phase, Leonilson deliberately restricted his universe of signs. He developed his own vocabulary, with themes of love and eroticism at its core. Recent readings of his work have highlighted not only its emotional and intimate aspects but also the political dimensions of Leonilson's aesthetic choices. 

Artista ceareanse, que construiu sua carreira em São Paulo, José Leonilson é considerado um dos principais nomes da Geração 80A native of Ceará who built his career in São Paulo, José Leonilson is considered one of the leading figures of the 80s Generation, a group of artists associated with the return to painting and the development of an expressive, gestural, and pop language. Marked by vigorous gestures and intense colors, Leonilson's early works sparked interpretations linking them to the Italian transavantgarde. Among his most significant influences are the works of Antonio Dias, Keith Haring's graffiti, and Paul Klee's watercolors. His early pictorial production, developed between 1983 and 1988, is characterized by a search for the "pleasure of painting," combined with the freedom of gesture. The favored medium is canvas, without a frame, in large-format works. 

By the end of the 1980s, Leonilson began to take a different aesthetic path from his earlier work. Notably, his focus on words and body cartography emerged, using a complex universe of references and graphic symbols. Among the systematically created images are the atom, the tower, the heart, the ladder, the open book, the mountain, the volcano, the spiral, and others, overlaid by the artist, such as fire and water, the compass and the clock, the hourglass, and the mathematical symbol for infinity.

Leonilson's mature work reflects on the delicate boundaries between what can be said and what belongs to the realm of the unspeakable, creating a diary that is both personal and open. According to Lisette Lagnado, "Leonilson was driven by the compulsion to record his inner life and dedicate it to the objects of desire."

From 1989 onward, his work took on a more intimate and delicate tone. At this moment, the artist began to employ new techniques, incorporating stitching and embroidery. The personal and autobiographical nature of his work intensified in pieces created after 1991, the year he discovered he was living with the HIV virus. With direct repercussions on his poetic language, the discovery of his illness pushed Leonilson to develop new metaphorical ways of expressing his personal experience. The generally small format of the works from this period accentuates the intimate and simple quality that drives Leonilson's expression. 

Leonilson's works are often metonymies of his own body and confront the dangers of exposure to the gaze of others. He also frequently plays with references that confuse the viewer about the factual or fictional nature of his works. According to Adriano Pedrosa, "Each word in Leo's vast and rich lexicon fights fiercely against becoming dictionary-like." 

Works by José Leonilson are part of numerous public collections, both in Brazil and abroad, including: Centre Georges Pompidou, Paris; Tate Modern, London; Museu Serralves, Portugal; Museo Nacional de Bellas Artes, Buenos Aires; Museum of Modern Art, MoMA, New York; Städtische Galerie; Museu de Arte Moderna de São Paulo, São Paulo; Instituto Moreira Salles, Rio de Janeiro; Instituto Inhotim, Brumadinho; Museu de Arte Contemporânea da USP, São Paulo; Pinacoteca do Estado de São Paulo, São Paulo; Museu de Arte de Brasília, among others.