The son of a lithograph salesman, Oscar Berninghaus was educated in St. Louis grammar schools. Even then he sold spot news sketches to the local newspapers. In the tradition of an earlier era of painters, he began work in lithography in 1889 and as a printing apprentice in 1893. Meanwhile, he attended night classes at St. Louis Society of Fine Arts for three terms. Established first as an illustrator and then as a largely self-taught fine artist, he was in the course of getting his first one-man show in St. Louis in 1899.
That year he was the guest of the Denver and Rio Grande Railroad on a junket to Colorado. Intrigued by tales of Taos, New Mexico he made a brief side trip twenty-five miles by wagon to the still-untouched village. He returned to Taos each summer after that staying for longer and longer periods until he settled there permanently in 1925.
A member of the prestigious Taos Society of Artists, he created paintings that were of the Pueblo Indians, the Spanish Americans, the adobes and the mountains, generally with at least one horse. With his practice as a lithographic artist and illustrator, his approach was direct and objective, showing the Indians as they were rather than posed or nostalgic stereotypes.
His technique was to work out of doors, painting on the scene. After he moved to Taos, his style became more modern. His compositions were more complex, his colors richer, and frequently he painted from memory at his easel within his studio.
Known as one of the greatest Taos pioneer painters, his works are highly sought after today and are held by many important private and museum collections including the Amon Carter Museum of Western Art, Museum of New Mexico, Philbrook Art Center, City Art Museum St. Louis, Gilcrease Museum, the Eiteljorg Collection and the Anschutz collection.