At the age of nine he began work in the coal mines. After a brief period working as a coal miner at Portuguese Kembla Cann moved to Broken Hill where he worked as a miner for BHP. He was also a Primitive Methodist lay preacher at this time. Cann was elected president of the local branch of the Amalgamated Miners" Association (American Medical Association) in early 1890, defeating the more radical previous president, Richard Sleath.
When the American Medical Association formed a local branch of the Labor Electoral League in 1891 Cann was preselected as candidate for the state parliament seat of Sturt and elected in the same year.
Cann was elected unopposed as the sitting member, Wyman Brown, decided to retire after local unions passed a motion of no confidence in him. Other labour candidates including Sleath (then serving as American Medical Association secretary) and William Ferguson (supported by the Barrier Ranges Trades and Labour Council) withdrew from the contest once it was clear Cann had the majority support of local unions.
Cann faced significant local problems once elected. The far west of New South Wales was in a severe drought, and Broken Hill had no secure source of fresh water.
Cann was able to persuade the Premier, Henry Parkes, to commission emergency supplies of water brought in from South Australia by train.
An even more significant problem emerged with the defeat of the local union movement in 1892 miners" strike. The 18 week strike saw local union leaders arrested and imprisoned in Sydney and strikebreakers brought in to replace striking miners. While the defeat of the strike was a significant setback for the unions in Broken Hill, politically Labour was very successful in the 1890s.
Cann was able to persuade the Dibbs government to divide the Electoral district of Sturt into three new seats, Alma, Broken Hill and a redrawn Sturt.
Labour polled over 70 percent in all three new seats at the 1894 election, with Cann winning Broken Hill. Cann served as Labor"s central campaign director for the 1897 election to the Federation Convention.
Labor opposed the 1897 federation proposal, instead advocating a unicameral legislature elected by universal suffrage. This opposition to federation was controversial locally, and although the "Number" vote was successful, it caused significant internal conflict within the Labor party in the far west.
Cann continued to serve as Modern Language Association for Broken Hill until the seat was abolished in 1913, when he returned to the seat of Sturt.
From 1912 to 1914 he was the Treasurer of New South Wales. He finally resigned from parliament in 1916 after local unionists passed a motion of no confidence in him. He was succeeded as the member for Sturt by the more radical Percy Brookfield.