Robert Mackintosh was employed by the Australian Agricultural Company as assistant Surgeon at Stroud.

On the 8th September 1841, he travelled from Stroud to Sydney to testify at the trial of  John Kelly who had been accused of the murder of an aboriginal boy Jacky Smith.  Dr. Mackintosh may have travelled on one of the steamers that regularly travelled between Newcastle and Sydney. Although his travelling expenses for the journey were reimbursed, when he applied to Justice Stephen for remuneration for his attendance as a professional man, his request was denied.

In 1845 he was residing at Maitland where he was a Judge of livestock at the Hunter River Agricultural Society ploughing match in April of that year

Robert Mackintosh later moved to Tamworth.