He wrote poems and analytic essays for the school newspaper, in which he argued that African Americans needed to show "ability, aggressiveness, and cooperation" to succeed.
Fontaine married an acquaintance from Philadelphia in 1936, Willabelle Hatton of Iva, South Carolina; they had two daughters, Jean and Vivian.
For example, politicians offered employment to blacks during World War I not in order to achieve occupational racial equality, but to avert defeat by Germany.
During the Truman and later McCarthy eras, Fontaine supported the presidential candidacy of socially liberal Republican governor Harold Stassen, who served as President of Penn from 1948 to 1953.
Fontaine expounded his civil rights views in Reflections on Segregation, Desegregation, Power, and Morals, published in 1967.
Interested in growing African nationalism in the era of decolonization, Fontaine traveled worldwide to discuss Pan-African issues.
Two years later, as secretary of the American Society of African Culture, he attended a conference on socialism called by Senegalese President Léopold Sédar Senghor.
In his honor, the University of Pennsylvania established the Fontaine Fellowships in 1970, awarded to "provide the additional funds necessary to students from underrepresented minority groups to pursue full-time doctoral study".