Mott was born in Rose Hill, Iowa. His parents were Mary E. (Tipton) and David Charles Mott, publishers of the weekly What Cheer, Iowa Patriot. The Mott family owned a print shop in Keokuk County. He was a practicing Quaker.
He taught English at Simpson College in Indianola, Iowa and was the head of the Journalism Department at the University of Iowa (UI) for twenty years until his appointment as Dean of the University of Missouri (MU)'s School of Journalism in 1942.
He may have coined the term photojournalism in 1924, Mott was influential in the development of photojournalism education: the first photojournalism class was taught at UI during his tenure, and the first photojournalism program, directed by Clifton C. Edom, started at MU in 1943 upon his request.
^Stroebel, Leslie D. and Richard D. Zakia. The Focal Encyclopedia of Photography. Boston: Focal Press, 1993. - This is greatly contested; others claim it was Clifton C. Edom, Henry Luce, or various other photojournalists.