Born into an aristocratic family in Bogotá, his father was the Conservative party leader Luis Martinez and his mother Mercedes Delgado Mallarino.

It was a difficult childhood due to his father's expulsion from Colombia as a result of an indictment for his involvement in an earlier Coup d'état.

In 1925, he moved to Cartagena, where, at the age of 18, he directed and illustrated some sections for the newspaper "La Patria" under the pseudonym of "Sanmardel".

In Chicago, Martínez befriended and worked alongside Edward Hopper, Isamu Noguchi, Willem de Kooning[citation needed] and Edgar Kaufmann Jr., among others.

Shortly after, he won the Logan Medal for the Arts for his mural: "Colombian evolution" at the 1933 Chicago International World Fair and exposition.

At the fair, Martínez also assisted with the Murals at the General Motors Exhibit, as Diego Rivera's commission was cancelled due to the Lenin controversy in New York.

Martinez, who was an avid historian and protector of the Colombian artistic heritage, discovered a painting by Raphael de Urbino.

General George Marshall of the US called the piece a wonder of contemporary art,[11] and was relieved that the capitol was spared from the fires during the Bogotazo.

In the following years, he made various well-recognized brand logos, illustrations, history books, and over 30 majestic murals in addition to many of his best known paintings.

During this period, he wrote and directed the dramatization of radio scripts, such as "El Virrey Solis", that broke all the ratings records for that year.

Rockefeller, in a speech during the presentation of the painting to the public, called Martinez Delgado "the greatest Latin American artist of the decade".