Born in Colyton, near Penrith, west of Sydney, the son of a hotel keeper, Smith was educated at public schools before gaining work with the railways. Following his marriage in 1879, Smith turned to auctioneering and grazing before following his brother, Thomas Richard, into Parliament.
While not a parliamentarian, Smith served on the executive of the Free Trade Party and began planning his campaign for a seat in the new federal parliament. He decided to contest Macquarie at the first federal election in 1901 but was given little chance of victory by observers and the local press, who pointed to his earlier anti-federal views and his recent electoral losses as proof that he exercised little influence amongst the electorate. Smith, however, gained the endorsement of the local branch of the influential Loyal Orange Lodge and the support of Free Trade Party leader George Reid—who enjoyed a large personal support amongst voters—and was elected. In 1903, he again won Macquarie, defeating William Sandford.
Smith served as a senior member of the Free Trade Party in opposition before helping to engineer the downfall of the Chris Watson government and its replacement by George Reid as Prime Minister. Widely considered Reid's most faithful henchman during his time in parliament, Smith was made Postmaster-General by Reid but retired from political life following his defeat at the 1906 elections.
Smith died in Sydney on 21 February 1934, preceded by his wife and youngest son, killed during the Gallipoli landings. Smith's eldest son, also named Sydney, served as president of the New South Wales Cricket Association from 1935–66.[6]