Arnold Blanch was born in a small town in southern Minnesota, June 4, 1896. His mother painted china and his aunt painted reproductions of painting she used to decorate her home. After his family moved to Minneapolis, Blanch attended the Minneapolis School of Art from 1916 to 1917. Blanch's art studies were postponed when he became a soldier in World War I. This was his first trip to Europe and he was able to see Paris and the Louvre. Upon his return to the United States, Blanch settled in New York and attended the Art Students League from 1919 to 1921. He was taught by Kenneth Hayes Miller, John Sloan, and Boardman Robinson and attended lectures given by Robert Henri. Through Henri, Blanch was introduced to the writings of Walt Whitman, who gave him a new sense of values which affected the content of his paintings.
Blanch moved to the art colony of Woodstock, New York around 1923. Blanch had two solo exhibitions at the Dudensing Gallery in New York in 1926 and 1929 which launched his career. In 1930 Blanch traveled west by car to teach at the California School of Fine Arts in San Francisco for a year. In California he discovered his love for teaching and became friends with Diego Rivera when Rivera was working on his City College murals. Blanch also met fellow artist Doris Lee while in California and they soon became romantically involved. They shared their lives for the next thirty years, living in Woodstock and traveling to many parts of the world together. Blanch taught at the Art Students League in New York from 1935 to 1939 and also taught at the League's Woodstock branch through the 1960s. Blanch received a Guggenheim Fellowship in 1933. In the Thirties he won several mural commissions through the Treasury Department, including the post offices of Fredonia, NY (harvest scene); Norwalk, CT; and Columbus, WI.
Between 1939 and 1942 Blanch spent summers teaching at the Colorado Springs Fine Arts Center where he took day trips to the gold mining towns of Cripple Creek and Victor in the mountains to paint landscapes. He spent the winter of 1939 in coastal Georgia and South Carolina, having previously spent time in 1936 in Savannah. In the late 1930s Blanch began to take guest instructor positions at many of Florida's art institutions from November to March, traveling with Doris Lee and often with Milton and Sally Avery. Palm Beach, Sarasota, and Key West were all on the annual teaching schedule.
Blanch wrote and published several books and continued to teach at various universities until his death in 1968.