Dennis was born in Wellington in 1951, but has spent most of his life in Christchurch. From an early age he demonstrated a strong interest and ability in graphic art. Under the tutelage of well-known artist and teacher Ron Naylor, his ability in pencil and graphite portraiture was finely honed. He is a master at portraying people of all ages, and pets of all kinds. Fastidious attention to detail is the hallmark of his work.