In his early years in Mexico City, he continued studying the art of painting under Antonio Rodríguez Luna, and considered him to be one of his primary teachers.
In 1961, Icaza founded an artist group called Los Interioristas or Nueva Presencia with painter Arnold Belkin.
The mural, La Farándula was dedicated to Bertolt Brecht as an apology for the world of clowns and actors, inspired by The Threepenny Opera.
Icaza also published several books, including La Fiera Malvada (1971), Me quiero ir al mar (1985), and Llegando a puerto en sentido contrario.
[4] Despite his strong criticism of the Mexican government during his life, he felt no contradiction in taking grants from official sources, saying that the arts of a country are always their best things to show to the world, and he is part of that.
[2] In 1993, he received a special grant from CONACULTA to return to Mexico and paint in oils full-time, after his work on drawings that expressed his wishes to "leave by the sea" (Me quiero ir al mar).
After the murals were shown to the public in their new location in 2004, Icaza and other artists denounced the works as copies or fakes, claiming the originals were destroyed.
His production had marked periods, from neo figuration to criticism and from there to works that recall the ancient cultures as humorous and satirical recurrences.
He produced a series of oil paintings and drawings of prostitutes and the Lumpenproletariat that shows influence from German Expressionism and symbolist painter James Ensor .
[2] The artist states that while he has changed styles and techniques, elements of expressionism remain constant in his work,[12] stating “When I draw I try to transmit my obsessions as a thinking being, as a vital part of the 20th century; my usual themes are life and death.”[2] Icaza produced gouaches, engravings and drawings conceived in book form such as La fiera malvada, Animales míticos, Breve historia de una mano juguetona, El viaje erótico, Sancho escuchando la lectura del Quijote, Me quiero ir al Mar and Llegando a puerto en sentido contrario.
He was a friend of Ray Bradbury and Aldous Huxley and admirer of José Clemente Orozco, all of whom affected his work, as well as his political ideas, which were strongly socialist and did not change over his life.
[4] Icaza was well-versed in contemporary and past artistic movements, and also had ample knowledge of ancient cultures and the literatures of various countries and epochs.