Merriam attended the University of Chicago, where he starred in football and track between 1905 and 1908. He was a member of the American track and field team at the 1908 Summer Olympics in London. In the 400 metres, Merriam won his preliminary heat with a time of 52.2 seconds. He advanced to the semifinals, where he finished third in his heat to be eliminated from further competition—the only 400-meter race he ever lost.