Denton enlisted in the Metropolitan Rifle Volunteers (part of Western Australia's colonial forces) in November 1899, as a second lieutenant.
However, on the outbreak of the First World War he enlisted in the Australian Imperial Force, commanding a company of the 11th Battalion and receiving a corresponding promotion to major in January 1915.
He remained on duty for some time before being evacuated, during which he helped to organise the transmission of information between the onshore artillery and the offshore naval support.
Denton was mentioned in despatches for his actions, and later in the year was awarded the Distinguished Service Order (DSO), becoming the first officer of the 3rd Brigade to receive that honour.
[2] After leaving the army, Denton began farming in Berkshire Valley, a locality near Moora (a small Wheatbelt town).
Motivated by the need for adequate political representation for returned soldiers,[2] he entered parliament at the 1921 state election, standing as one of three Country Party candidates in the seat of Moore.
Denton was re-elected with an increased majority at the 1924 state election, defeating three candidates from the opposing Executive (or Opposition) faction.
[1] At the 1927 state election, Denton suffered a large swing against him and was defeated by Percy Ferguson, a farmer from Moora standing for the Country Party.