Colton, however, found work in Adelaide, and at the age of 19 began business for himself as a saddler. He was shrewd, honest and hard-working, and his small shop eventually developed into a large and prosperous wholesale ironmongery and saddlery business, John Colton and Company, which became Harrold, Colton & Company in 1889, then in 1911 Colton, Palmer and Preston Ltd., at the Topham Street corner of Currie Street, which firm survived as hardware merchants well into the latter half of the 20th century.