Giuliani announced the lawsuit in New Hampshire.
He claimed Biden's comment harmed him.
Giuliani faces legal issues and questions about paying his legal fees.
Another lawyer representing him withdrew in a Georgia election case.
Giuliani addressed concerns about his drinking habits mentioned in investigations.
He denied having an alcohol problem.
The lawsuit revolves around Biden's remarks about Russian interference in the 2020 election.
Biden had stated that Giuliani was being used as a "Russian pawn."
Giuliani insists Biden's comments are false and damaging.
He emphasizes the lawsuit is not a retaliation against Hunter Biden's previous lawsuit.