Born in St. Paul, Minnesota, Theodore Van Soelen began his art training as a student at the St. Paul Institute of Arts and Sciences from 1908-1911, and then studied at the Pennsylvania Academy of Fine Arts. From that institution, he won a Cresson Traveling Scholarship for travel and study in Europe in 1913 and 1914. He traveled West to Utah and Nevada and in 1916, and to New Mexico where he worked in Albuquerque as a commercial illustrator and began selling his first paintings. Wanting to get a better understanding of the Native American and cattlemen's way of life, he lived in towns and ranches throughout the state and spent a year at San Ysidero's Indian Trading Post. During this time, Van Soelen had a one-man exhibition of his work at the Cincinnati Art Museum, which brought him national attention.
In 1922 Van Soelen moved to Santa Fe, New Mexico, and in 1926 became a permanent resident of the Village of Tesuque. His popularity developed a strong market for his paintings in the East and he established a second studio in Cornwall, Connecticut. His specialty was ranch scenes done in a realistic illustrative style, but also became a noted landscape and portrait painter, with scenes tempered by rearrangement of compositional elements.
He was elected a National Academician at the National Academy of the Arts in New York City and continued to exhibit in the East at the National Academy, the Metropolitan Museum of Art in New York City, and the Chicago Art Institute. At the same time, he was active in New Mexico and completed numerous landscape paintings and a mural in 1938 for the Post Office in Portales. In 1960, he was named Honorary Fellow in Fine Arts by the School of American Research of the Santa Fe Museum.