In September, 1867, he entered the Hudson River Institute (later known as Claverack College), a military academy in Claverack, New York. He also attended religious services at the Dutch Reformed Church. In September, 1870, he enrolled at Rutgers College. He obtained a classical education, studying among other subjects Latin, Greek, Mathematics (including algebra), Natural History (including physiology) and Rhetoric. He was a member of Rutgers' football team. Although Clum was on the team, he did not play in the first intercollegiate game between Rutgers and Princeton on November 6, 1869, but played in the second game in the fall of 1870. Clum's strenuous activity and competitive athletics left him ill and in his second year of college he was unable to earn enough money to pay for his tuition. He returned to his father's farm in the summer of 1871.