Before coming to Rhetoric at Iowa, Dennis was a postdoctoral intern in linguistics and the teaching of writing at Temple University (Philadelphia) and a Mellon Fellow in the Department of English and the Literature and History Program at Washington University (St. Louis).

He has been a leader in Rhetoric's Professional Development Program (PDP) every year since 1981 except for a term as Department Chair (1989-1992) and Director of the (now defunct) Reading Lab.Dennis has a longstanding interest in educational technology and was on the team that created Library Explorer, http://explorer.lib.uiowa.edu. His research centers on Renaissance studies, with publications on Elizabethan political poetry and the sixteenth-century controversy over whether a woman could rightfully rule England.