One of the first great athletes at Idaho, Edmundson competed on the track for the Vandals, launching the team onto the national stage when he and two other athletes traveled to the Lewis and Clark Exposition Games against the top schools in the Northwest. Newspapers wrote that Edmundson “impressed with his graceful form and unfaltering determination.” He is responsible for organizing the Idaho cross country team in 1908, laying the foundation for a team that would win nine Pacific Coast Conference titles. Also in 1908, Edmundson traveled down to Stanford for the U.S. Olympic trials, where he won the 800m and finished second in the 400m. Edmundson held the title of top half-miler in the country through 1912. He represented the United States at the Olympic Games in London in 1908 and in Stockholm in 1912, becoming the first Idahoan to compete in the Olympic competition. After his athletic success, Edmundson came back to Idaho as a coach for both track and basketball, compiling a 20-9 record in two seasons with the basketball team. He is perhaps most famous for his time as a basketball coach at the University of Washington, where he is credited with the creation of the fast-break offense style, which he attributed to his track background.