His first volume of poetry, 'A Summer of Love,' gained him fame and won him a spot in 'Who's Who' at age 25. In addition to becoming a well-known and well-respected poet, Kilmer also wrote book reviews for The New York Times and The Nation, and became a special writer for The New York Times Sunday Magazine. He worked on the staff of The New York Times for five years.

Kilmer, a deeply religious man, converted to Catholicism in 1913. His point of view on all matters of religion, art, economics and politics, as well as on all matters of faith and morals, was unhesitatingly Catholic.