In 1901, he left London for the United States, where he taught art at the California Art Institute in Los Angeles and at the Santa Barbara School of the Arts. He was employed as a scene painter for the movie industry. His first exhibition was in 1905, from which he gained immediate recognition for his talent. Fellow artists introduced him to the West as a subject and he began traveling and sketching throughout California and the Southwest. He was especially inspired by Arizona and New Mexico. He painted used various mediums including oil, watercolor, etchings, and woodblock. He was commissioned to paint posters for the railway company, Atchison, Topeka and Santa Fe Railway. Carl Borg was known for his dramatic paintings of the Grand Canyon.
Carl Borg became a protégé of American philanthropist and art patron Phoebe Hearst, who gave him the opportunity to return to Europe to study art for five years. While in Europe, he received awards in France in 1913 and 1914.
Borg was a founding member of the Painter’s Club of Los Angeles and the California Art Club. He was also one of the first art directors for a major movie studio in Hollywood. He was a member of the National Academy of Design, the National Academy of Arts, Société Nationale des Beaux-Arts and the Salmagundi Club. From 1925 to 1928, he worked with the production of silent films.
Oscar Carl Borg died of a massive heart attack on May 8, 1947. His art is on display at the Brigham Young University, Harvard University, Smithsonian American Art Museum and the Fine Arts Museums of San Francisco.