After leaving school, Ratten worked for the Union Bank of Australia in Forbes until 1898, when he and a friend announced their intention to travel the world by bicycle.

He later spent time in the United States and in March 1907 acquired a diploma of medicine at Harvey Medical College in Chicago.

He practised in Sheffield for seven years and was a health officer for the Kentish Municipal Council, also serving as a justice of the peace.

[3] Ratten was refused admission to the Tasmanian branch of the British Medical Association (BMA) after its formation in 1911, as it did not recognise his American qualification.

He had a reputation as a skilled surgeon, "insisting on extremely high standards of hygiene, theatre teamwork and modern equipment".

His oldest son John Richard Ratten was an officer in the Royal Australian Air Force (RAAF) and died in 1945 while on active service.