Mayser was the head college football coach for the Franklin & Marshall Diplomats located in Lancaster, Pennsylvania. He held that position for 3 different terms totaling 6 seasons: first from 1913 until 1914; second from 1924 until 1925, and third from 1944 until 1945. His coaching record at Franklin & Marshall was 25 wins, 21 losses and 3 ties. As of the conclusion of the 2010 season, this ranks him #6 at Franklin & Marshall in total wins and #17 at the school in winning percentage (). He also coached wrestling at F&M from 1924 to 1946.