Dennis was born, April 3, 1962. A child prodigy, he began playing the drums when he was two; and became a professional musician at the age of ten when he performed in the Anchorage Community Theatre's production of A Funny Thing Happened on the Way to the Forum. Developing his craft in various playing situations,
Dennis received numerous awards such as Who's Who in Music, 1979; National Endowment for the Arts grant for composition in 1983; and in 1992; Outstanding Alumni from the University of Nevada, Las Vegas. While attending UNLV, he was a member of the acclaimed UNLV Jazz Ensemble where his drumming and arranging skills caught the attention of vocalist Joe Williams. In 1981, at 19 years of age, Dennis moved to New York City and landed a gig as a drummer on Broadway.
His Broadway credits include The First and A Chorus Line. In January of 1983, Dennis joined the Count Basie Orchestra on the personal recommendation of Mr. Williams.
Dennis traveled extensively and worked alongside Mr. Basie until his death in April 1984. He continued with the orchestra under the direction of interim leader Eric Dixon followed by Thad Jones. In 1985 under Mr. Jones's leadership, the Count Basie Orchestra recorded one of Dennis's compositions entitled And That's That.
Dennis stayed with the band, when Frank Foster took over as leader, until December of 1987. Dennis's composition Bus Dust was included on the CD Long Live The Chief which was recorded during Mr. Foster's tenure as leader.