Dennis was born in Holbeck, Leeds, Yorkshire, and learned his cricket in the Scarborough district. He was a right-arm fast bowler, who took 163 wickets at 29.26, with a best of 6 for 42 against Northamptonshire, one of five five-wicket hauls in his career. He was also an aggressive left-handed batsman who scored 1,500 runs at 19.73, with a best of 95 against the West Indies tourists. He also took 59 catches. His best season was 1929, when he took 84 wickets; Wisden praised his pace, but not his accuracy.[2] He was unable to maintain his best form, and played most of his cricket in the 1930s in the leagues and for Cheshire in the Minor Counties Championship.[2] He played for Heckleton Main, Hull, Baildon, and Undercliffe and scored over 1,000 runs as a professional for Oxton (Cheshire) in 1935.
He is part of a cricketing dynasty. His brother-in-law was Len Hutton; one of his nephews, Richard Hutton, likewise played for Yorkshire and England; other nephews, Simon Dennis, played for Yorkshire and Glamorgan, and John Hutton played a game for the Marylebone Cricket Club (MCC).[2]
In 1948, he emigrated to New Zealand to take up fruit farming near Christchurch, and became a selector for the Canterbury Cricket Association. He and his wife Margaret had two sons and a daughter. One of their sons, Andrew (1944–2016), was a noted conservationist and author, and was awarded the MNZM.[3]
Frank Dennis died in November 2000 in Christchurch at the age of 93.