"[2][3][4][5] Robertson served in France during World War I, and played on an armed forces football squad in Saumur.

[6][7] Upon returning home from war, Robertson played college football for Dartmouth, where he captained the team in 1920 and 1921, was named an All-American in 1919, 1920 and 1921, and was referred to as "one of the supermen of the modern game.

In 1919, he made a 50-yard drop kick field goal at the Polo Grounds in Dartmouth's 9–0 victory over Cornell.

[10] In 1921, Robertson suffered a leg injury late in the season, forcing him to move from halfback to lineman in his final game with Dartmouth.

He reportedly opened "gaping holes" in the Georgia defense, and Dartmouth came out of Atlanta with a 7–0 victory.