[4][5] Conn started to experience progressive hearing loss as a child of 12; he describes his father as having encouraged him to overcome the challenges posed by his deafness.

[1][2][4] He attended Wesleyan University, where his father had started an early course in bacteriology,[1][2][6] gaining a doctorate in 1908, despite being obliged by his deafness to copy another student's lecture notes.

He completed this PhD in 1911;[1][6] his thesis is entitled "A study of seasonal variation among the bacteria in two soil plats of unequal fertility".

He spent his entire career at the station, which became part of Cornell University, being appointed chief in research in 1920 and, in addition, professor of bacteriology in 1945.

[2] Conn published more than 200 journal articles, predominantly in the fields of soil microbiology and bacterial staining techniques.

[6] He wrote two biographies of his father, Herbert William Conn: one appears in Bacteriological Reviews and deals with the foundation of the Society of American Bacteriologists; the other unpublished text, "A Religious Scientist at the Turn of the Century", includes a bibliography.

[2][13] His papers are archived at the Division of Rare and Manuscript Collections of Cornell University Library.

[1][2] He was married; he and his wife had a son and a daughter, Jean, who also became a bacteriologist and was Conn's long-term assistant.