Asplin entered F&M in 1935 as a scholarship athlete and gave the college no reason to doubt that it was money well spent. During Asplin's three varsity years at F&M, the Diplomats were 7-1-1 in 1936, 4-4 in 1937 and 6-2 in 1938 for a total record of 17-7-1 in football. It is important to note that freshmen were not allowed to compete in varsity athletics. In 1936, when Asplin made the varsity squad, Coach Al Holman changed his system from the double wing to the single wing, in which the left halfback (Asplin) called the plays instead of the quarterback.
Asplin had great speed as a ball carrier. In a crucial game against Muhlenberg in 1938, he gained 129 yards on 11 carries as the Diplomats won 20-7. Due to Franklin & Marshall not sponsoring baseball from 1931 to 1943, Asplin did not have the opportunity to compete in the sport in which he excelled. While at F&M, Asplin earned six varsity letters and was a member of the 1936 league champion football and basketball teams. Following graduation, Asplin played second base for Allentown in the newly formed Class C Interstate League, leading the team to the league championship in 1939 with a .325 average.
In 1940, he was invited to spring training by the Boston Braves who acquired Asplin from Allentown for cash. Following spring training, he was sent to Bradford in the Pony League where he played with future Hall of Fame pitcher Warren Spahn and batted .305 for the year. In 1942, he began working for Armstrong as personnel manager of the plant engineering and maintenance department, retiring after 40 years.