His prolific career has been commonly associated with Abstract Expressionism, exploring themes approaching political and social criticism, still lifes, and Colombian nature. Obregón's work, which encompasses the production of easel paintings, murals, cultural management, and education, is considered one of the most relevant and influential in Colombian modern art. Marta Traba, the best critic of his work, wrote in 1961: "The arrival of Obregón to Colombian painting places us before the first talented Colombian painter in this century [...] The artist's work shows clear development and its evolution is full of indications that unequivocally demonstrate the alliance of talent and hard work."