In 1827 he became an assistant at a mental institution in Heidelberg, and from 1835 to 1842 was director of the asylum.
At the Heidelberg asylum he was distressed by the conditions he experienced, and in collaboration with physician Friedrich Groos (1768-1852), he developed plans for construction of a larger, more modern facility.
As a psychiatrist Roller was vehemently opposed to "city asylums", a standpoint which placed him at odds with a number of his contemporaries.
He believed that an isolated non-urban setting such as Illenau was beneficial for a patients' return to mental health.
In addition, he stressed the importance of separating the patient from his/her familiar surroundings.