Born on Long Island, New York, Hobbs became the youngest and tallest jockey to ride the winner of the English Grand National when successful on Battleship, a son of Man o' War, in 1938 just three months after his 17th birthday.
At the end of the 1937–38 season, during which he rode 35 winners, he became the first jockey to win three Grand Nationals in one year, lastly the Cedarhurst version.
In the event, he was booked to ride a horse called Flying Minutes and was amongst the leaders until falling at the last open ditch.
In 1938, he finally got to ride and win aboard Battleship, a horse that was completing a unique American and Aintree National double.
Shortly after the war, Hobbs became a private trainer for John Rogerson at Letcombe Regis in Berkshire.