Dennis was a right-handed batsman. Dennis made his first-class debut for Essex against Glamorgan in the 1934 County Championship. A further first-class appearance came in 1936, while in the following three seasons he made a handful of appearances in each, making a total of 22 appearances between 1934 and 1939.
In his 22 first-class appearances, he scored 530 runs at a batting average of 17.66, with a high score of 53.
This score, which was his only first-class fifty, came against Sussex in 1937. He died on 21 August 2006.