As a 12-year-old he worked at a garage helping to build engines for five shillings a week, before going to England in 1912. He became immersed in aviation, began instructing novice flyers, and managed hangars at Brooklands aerodrome, the hub of British aviation. Having established his name as an aviator he became chief test pilot for Tom Sopwith who was already recognised as the originator of many fine aircraft..

In 1914 Harry Hawker returned to Australia to demonstrate the advanced Sopwith Tabloid which he had earlier helped design. A wild crowd nearly wrecked the plane on one occasion and he further damaged it during stunt flying, so he went back to England.

World War One saw him kept in England designing and testing production aircraft. In 1919 he attempted to fly the Atlantic in a triplane and disappeared. Six days later he turned up in Europe aboard a tramp freighter without a radio. He won the Daily Mail prize of 5000 pounds, however. He was killed in 1921 when his plane crashed while practicing for an airshow . He had spinal tuberculosis and that plus a fire in the air were considered contributing factors.

Not many months before this his surname was deliberately chosen as the name of a new aircraft company. The mighty Sopwith Aviation Company was liquidated in September 1920 because there were fears the government would examine the wartime aircraft production contracts of the various companies such as Sopwith and would impose crippling retrospective tax liability on them..

About the same time, Tom Sopwith, Fred Sigist, Bill Eyre and Harry Hawker together formed a new company, each contributing 5,000 pounds. To avoid any possible government claims against the new company for the wartime contracts of the old company, the new entity purposely avoided using the Sopwith name and chose the name Hawker.