Dennis was born in Chadron, Nebraska and spent summers growing up on a cattle ranch in the Sand Hills of Nebraska. He moved to New York City in 1959 and spent 20 years there. Teaching guitar at the New York College of Music, Metropolitian Music School, Brooklyn Music School, Henry Street Settlement, and Jersey City State College kept him busy as he studied guitar with Albert Blain and attended master classes of Jose Tomas and Narcisco Yepes. In 1979 he moved to upstate New York where he teaches at the State University College at Oneonta and at Hartwick College. He is an active performer on the classical guitar, both in jazz and classical styles of music. As a composer he is entirely self taught.