While he designed several entire buildings, he is most noted for the exquisite interiors he created for buildings done by other architects. He became one of Chicago's most sought-after interior designers following his work at the Mansion.
The Hegeler Carus Mansion is perhaps the most intact example remaining of his interior work and a rare example of high-style Victorian interiors in general. The Mansion interior is virtually unchanged since the 19th century. It is faded, but still original. Restoration of the original decor is on-going. The result is an extraordinary glimpse into the unity of architecture and interior decoration.