The council took the case to court, where magistrates referred it to the Crown Court in Kingston, which fined Johnson £80,000, plus costs of £42,500. The previous highest fine was £56,000, the council said in a statement.
The judge said the high fine was warranted due to the financial benefit, level of culpability and the harm involved.
During the case, the prosecution argued that the demolition had been carried out for "financial benefits" and that Johnson had done it to save himself about £318,000 in building costs, as it was cheaper to build from scratch rather than refurbish the existing property.
However, the defence maintained that Johnson had made a genuine mistake and was sorry for his actions.
Virginia Morris, Richmond Council's cabinet member for environment and planning, said: "I hope that this will now demonstrate to residents and other developers in the borough that planning regulations need to be taken very seriously and cannot be disregarded or disrespected.
"I hope this will serve as a deterrent to those considering not complying with planning and conservation requirements. Those who flout the law in such matters will have to face the consequences."