He was born in Somerset, England, worked as a railway clerk and emigrated to Western Australia in 1880. Hector Rason became a storekeeper at Toodyay and at Guildford (east of Perth), then in 1893 went to the new Coolgardie goldfield as a mining agent and auctioneer. He later moved to Mount Magnet in the Murchison. In 1897 he was elected both Mayor of Guildford and Member for South Murchison, sitting as a supporter of the Forrest government. When the South Murchison seat was abolished Rason was elected as member for Guildford in 1901. He made his mark as Minister for Works in the Leake and James governments, and after Labor took office in 1904 became Leader of the Opposition.
When the Daglish governmemnt was defeated Rason in turn formed a minority government but was granted an early election in October 1905. A united Liberal Party enjoyed a sweeping victory over both the ALP and the remaining Independent members. Hector Rason did not provide firm leadership as Premier, dogged by family and financial worries. In May 1906 he appointed himself as Agent General in London before resigning as Premier, an action which drew strong criticism. After his term expired in 1911 he pursued a business career in Britain.