Olaf began his art training at the age of 12. His family, with their meager means, managed to enroll him in the Danish equivalent of a private school. Here his deft drawing abilities were discovered inspiring his family and teacher to install him at the Technical Society. The Society was a primer for promising young artists considered potential material for the Royal Academy. His hopes for a continued education were dashed when an upheaval in his family resulted in his mother and himself boarding a ship bound for America. Olaf and his mother arrived in New York on July 12, 1892 and boarded the transcontinental train. Five days later they disembarked in Great Falls, Montana. Olaf worked as a cowboy his first year in Montana, supplying horses for the Yellowstone Stage Lines. The next year he was an apprentice machinist for the Great Northern Railroad, then a locomotive repairman. At 20 he was inspired by a Canadian patron to begin working in oil. Seltzer's style reflects the influence of his friend Charlie Russell, who had encouraged him as well and painted with him on the many outings they took together. His friend ship with Russell brought Seltzer into the company of many famous patrons and bolstered his growing success. When he was 44 he was laid off by the railroad company and took up painting full time. As a traditional Russell-school Western painter he was very successful. In 1926 he moved to New York to complete several Russell commissions and continue his own work. In 1930 he was commissioned by the wealthy Dr. Philip Cole to paint the series of miniatures on Montana history. Going nearly blind he completed over 2,500 paintings. By 1936, he returned to Montana where he lived for the rest of his life. His works are held at the Gilcrease Institute of American History and Art ( 234 paintings), Amon Carter Museum, and several private collections.