Florian Philippot's decision, announced on French broadcaster France 2, comes a day after he was stripped of his party responsibilities for strategy and communications by Le Pen for refusing to leave the presidency of his association Les Patriotes [The Patriots].
His departure threatens to split the party.
Mr Philippot said he did not "like being ridiculed".
Philippot played a key role in Le Pen's effort to scrub clean her party's racist and anti-Semitic image to make it more voter-friendly.
Philippot claimed that the party's "old demons" were sneaking back into the party, a reference to hard right values. Philippot created his own political movement within the National Front to protect this major point of the party's program.
"The great enterprise of refounding the national movement to which I invite you ... but also all French people, is inspired only by duty: the duty to take action and to win so that France can remain France for its children and for the world", Le Pen told supporters September 9 in the village of Brachay, according to Deutsche Presse Agentur.
Philippot has always been one of Le Pen's closest allies.
Mrs Le Pen, who pledged after losing the presidential race to Emmanuel Macron to be the "main voice of opposition" against the new centrist government, has been overshadowed of late by far-left rebel and former presidential candidate Jean-Luc Mélenchon, whose working-class rhetoric and unabashed criticism of the young president have widened his support base. It has played out on TV in numerous interviews by Philippot and party officials.
"One should stop trying to bury the National Front", she told LCP television. Le Pen and Philippot never had a direct meeting about their differences, both say.
Jérôme Fourquet, an expert on the far-right at polling group Ifop, said Philippot's exit would deprive the party of experienced policy writers. "All those who have taken this road and led a solitary adventure have disappeared", Le Pen said.
Philippot was playing the role of victim, Le Pen said. She is heading into a party congress early next year in her most fragile position since taking over leadership of the Front from her father in 2011, with the only comfort being that there are no clear contenders for her seat.
Mexico City Mayor Miguel Angel Mancera said buildings at 44 locations had collapsed or were badly damaged. Geological Survey says the epicenter was in Puebla state, about 120 kilometers southeast of Mexico City .
Maraga said the opposition had failed to show evidence Kenyatta had campaigned using state resources or undue influence. Thousands of the forms were not made available, as legally required, by the time results were announced.
Tuesday and plans to have locations open later this year in Sudbury, Ont., Langford, B.C., Fredericton, and Toronto. Two years later he started selling toys, according before opening the first Toys "R" Us branded shop in 1957.
Trump's predecessor Barack Obama had temporarily frozen military aid to Egypt following a deadly crackdown on Morsi's supporters. The objective is "to reach a just solution based on the principle of the two-state solution and global decisions".
General Assembly: "It will be a great pity if this agreement were to be destroyed by rogue newcomers to the world of politics". From the beginning, the treaty was met with strong opposition from nuclear-armed states, which boycotted negotiations.
Rohingya fled their villages in the military crackdown that followed, and many of their villages have been burned. Promila Sheel, 25, said she made a decision to flee to Bangladesh after her husband was killed by militia.
It is expected that pilots at Dublin and Stansted - Ryanair's two biggest bases - will issue demands to management later today. Ryanair CEO Michael O'Leary said that some pilots were being offered a pay rise of 10,000 euros in exchange for helping out.
With baseball headed to an all-time high in home runs this season, a lot of players are doing things they have never done before. That was followed by a home run from third baseman Justin Turner to give the Dodgers a 2-0 lead five pitches into the game.
On September 3, Pyongyang detonated its sixth nuclear device, seen as the most powerful ever conducted by the Asian country. Japan appears to be taking no chances as they moved missile batteries to beneath the preferred flightpath of North Korea.
According to local media, two people - it claimed to be journalists - were left seriously injured after the military mishap. RBC news agency reports that the injured people "weren't civilians", according to comments quoted by The Guardian .
Julia Louis-Dreyfus Made Emmy History
She is also tied to Cloris Leachman for having the most individual Primetime Emmy Awards of any performer. She has five for Veep and one for New Adventures of Old Christine.
Kevin Hart and Eniko Parrish step out amid extortion scandal
When asked what the date was that Hart and her client were together, Bloom said it was "approximately a month ago in Las Vegas". The woman, Montia Sabbag , and her attorney Lisa Bloom , held a press conference in Woodland Hills Wednesday morning.
Ram Trucks Recalled for Fire Risk
The recall includes a total of around 494,000 Pick-up trucks from the Ram brand with model years from 2013 to 2017 . No injuries have been reported, but owners will be notified and can get a replacement at any dealer location.
Hurricane Maria On Track For Virgin Islands, Puerto Rico
The storm is forecast to move east of the central Bahamas - about 500 miles east of Florida - by this weekend, Shields said . The US National Hurricane Center upgraded the storm from category two to five in just a few hours.