West Ham moving in to the ground has angered Orient, who fear for their future as a result of the club moving into their neighbourhood.
Hearn said: “We are taking action against Newham Council because the loan is unlawful.”
“We will follow this with judicial applications against the Government, the Minister of Sport, the Mayor of London and will take action against the Premier League for being in breach of their own rules as well.
“It is an all-encompassing charge by Leyton Orient, a battle by the little man against the big forces of evil if you like.
“This represents a challenge to our entire future and our survival and we have no choice but to fight our corner.”
