Taking to Twitter, Le Pen wrote "I believe in the victory of Trump", having previously written that the billionaire is "an independent candidate with populist language, this is what made him successful."
The support from Le Pen comes at a time when he is engaged in a battle against his daughter Marine Le Pen over the future of the party. Marine is currently trying to "detoxify" the National Front.
But Jean-Marie last month warned Marine that he could launch a rival political group if she does not heed his advice and meet before this summer to discuss his expulsion.
Previously the National Front's honorary president, Jean-Marie was excluded from the party last August as the party sought to broaden its appeal and move away from its old anti-Semitic reputation.
Jean-Marie was suspended the previous May after repeating his view that the Holocaust was "a detail of history".
Meanwhile, Donald Trump is currently engaging in last minute campaign efforts across the US as five states go to vote tomorrow.
On another note, the National Front has indicated that they would like to use the surge in support Brexit to launch their own campaign that pushes for a so-called Frexit.