Georgescu made the comments outside the school in the village of Mogoșoaia where he had been due to cast his ballot before the constitutional court's decision came on Friday.
Supporters chanted "Georgescu for president" and "peace" as their candidate spoke. Supporter Sorin Scuratovschi said the court's decision was an attack on democracy.
Georgescu won the first round of the presidential election last week in a shock result amid allegations of Russian interference in the voting. That result has been overturned by the country’s constitutional court.
The court's decision plunged Romania, a member of the European Union and NATO, into institutional chaos and has raised concern that public trust in the state could be eroded. No date has been set yet for the re-run.