"I dare to repeat that the election of Donald Trump is good news for our country," said Le Pen, who will be the anti-immigration National Front's candidate in France's 2017 presidential election.
Le Pen, 48, was one of the first French politicians to react to Trump's stunning victory, tweeting her congratulations to the Republican president-elect "and to the free American people".
In her brief remarks later, she said a Trump White House would assure that the sweeping Transatlantic Trade and Investment Partnership (TTIP) between the US and EU would be rejected.
Le Pen said Trump would rein in "the warlike interventions that are the source of the huge migratory waves that we are suffering".
If Trump keeps to his pledges, they will be "beneficial for France," she said.
Le Pen is widely tipped to reach the second round of the French presidential election on May 7 next year.