Mario Igor Vargas was born in the city of Puerto Montt, where he had a peaceful and calm childhood. At a young age, he already had the desire to become a comics artist, especially for the magazine El Peneca, in which his idol Coré drew. Igor's talent was recognized early on; at the age of 14, he was already guided by painters like Hardy Wistuba and Pacheco Altamirano.
Igor went to Santiago to study at the School of Fine Arts, and during these years, he stayed in the home of Wistuba. By the early 1950s, he started to work for Chilean comics publications, mainly by the publishing house Zigzag. He did covers for Don Fausto and Okey, and contributed to Simbad and Aladino. He also fulfilled his childhood dream and worked for El Peneca.
Mario Igor proved himself a popular comics artist, who became known among friends and colleagues as "El Príncipe Negro". Igor, together with Abel Romero, became one of the main artists for Don Fausto, where he did illustrations and filled in lost pages from foreign series. Igor's payment was lower than that of his contemporaries, and it is said that this was because of his bad relationship with editor-in-chief Felix Lopez.
In order to promote the work of Chilean artists in newspapers, he helped set up the Sociedad Historietas Ltda., the Chilean union of comics artists. The group, that consisted of artists like Pepo, Lugoze, Abel Romero and the Argentine Miguel Gordon, launched the periodical El Mercurio. Igor began the historical series 'La Sombra de El Manque' in cooperation with Romero, but the project was cut short because of Igor's conflicts with Miguel Gordon.
Igor then turned to Okey magazine, and created what is considered the first great realistic comic strip in Chile, 'La marca del Escorpión'. He also went to work for other publishers than Zigzag, such as Imprenta Marinetti (Pimpinela). In the late 1950s, he returned to Zigzag however, and became the main artist for El Peneca, just like Coré was years earlier. In addition, Igor continued to work for the publisher's other magazines, like Condorito, based on the famous character created by Pepo. He also worked as a book and magazine illustrator.
In the 1960s, Igor and Abel Romero headed the comic strip department of Zigzag, which consisted of among others Lincoln Fuentes, Roberto Tapia, Pepe Orellana, Julio Berrios, Enrique Calvo, Germán Gabler, Avelino García, Guillermo Varas, Juan Francisco Jara, Máximo Carvajal, Manuel Cárdenas and many others. Igor worked with Manuel Cárdenas Arce on a series of comic adaptations by José Zamorano of the work of Jorge Inostroza, writer about the history of Chile. He also drew for Zig Zag's Aventuras de Walt Disney title from 1964, as well as the titles Robot and Rocket. In the historical magazine Hazañas, he drew 'Barracuda', and alternated with Romero on Jorge Inostroza adaptations. In the magazine El Intocable, he worked with his brother Hildegardo Igor, who was also a comics artist.
In Jungla, he made 'Elundi', and for Far West, he set up the series 'Ray Hunter'. Igor continued to work for Zigzag when it became Quimantú, after the coup in 1973. He drew the science-fiction/fantasy series 'Khanda' in Jungla, and made comics together with his brother for the new magazine El Intocable. In addition, he created the series 'Hijo de la Montaña', 'Yudex', 'Ki"o' and 'La Princesa y el Impostor' for the publisher Gabriela Mistral and its magazine Mampato in 1974. During the 1980s, he contributed to some Sunday supplements, but eventually the Chilean comics market folded. He missed the opportunity to accompany Abel Romero to work in Sweden, and spent his final years selling watercolor paintings. After some occasional contributions to comics magazines (La Papaya, Pim Pim, Dos Puntos, Asteroide, Bandido) in the 1980s and early 1990s, Mario Igor died from a brain tumor in July 1995.