The far-right leader, who lost out on the presidency in elections earlier this year, has finally won a seat in the French parliament on her fifth attempt.
The second round of legislative elections, her party Front National (FN) is expected to pick up between five and seven seats.
The 48-year-old was elected in the northern fiefdom of Henin- Beaumont, a former mining town, beating 12 other rivals.
She beat Anne Roquet, of Mr Macron’s La Republique en Marche (REM) party with 59 per cent of the vote.
She tweeted: “Thanks to the voters of the #Circo6211 and the mining area, as well as to all the French who have placed their trust in the #2ndTour!
“Tonight are elected, already, 6 members of the @FN_officiel including 5 in the mining area!
“We will fight with all our strength the deleterious projects of the Government. #Législatives2017”
But her righthand man, Florian Philippot, failed to be elected in Moselle, in eastern France.
Her partner and party deputy Louis Aliot won his seat in south western France.
The FN is expected to fall short of the threshold of 15 seats needed to form a group in the parliament, which would grant it greater access to finance and speaking time.
She said: “Its a scandal that our party that picked 7.6 million votes in the first round of the presidential election and three million more in the second round, cannot form a group in the French parliament.”
Marine Le Pen was resoundingly beaten by centrist Mr Macron in the presidential election, in May, after making it through to the second round.
Exit polls, released at 8pm local time (7pm BST), predicted Mr Macron’s party winning 352 seats along with its ally Mouvement Democrate.
Even without its ally it is expected to secure 309, far ahead of the Socialist Party and allies on 50, La France Insoumise on 30 and the Front National on 8.
In total Mr Macron and his allies are predicted to have 352 seats.
The right-wing FN had hoped to pick up 50 seats,…