Dennis made his debut for Exeter City as a 17 year old against Yeovil Town in a Southern League match on the 27/8/1955, eventually playing 8 matches in the Southern League that season.
Dennis was from Ladysmith School and had played for them in the early 1950's 

In August 1956, he signed pro-forms, whilst working as an apprenticed mechanic in Exeter, later in the season he played for the 1st team in a floodlit friendly against the Manager's All Stars.

He continued to play in the following two seasons and in 1956/57 played 19 games for Exeter in the Southern League. 

Dennis played for the reserves and in the Festival of Sports matches in 1957/58 for Exeter City.