Aliot was born in Toulouse, Haute-Garonne, to a family of ethnic French and Algerian Jewish heritage, who had resided in Algeria (Pied-noir). In the 1998 French regional elections, he was elected regional councillor of the Midi-Pyrénées and represented the department of Haute-Garonne during six years.
He then became a close collaborator of FN leader Jean-Marie Le Pen and played an active role in Le Pen's 2002 electoral campaign. He was sent to Perpignan to re-launch a divided and weakened FN federation.
In the 2004 regional elections, he led the FN list in the Midi-Pyrénées and polled 11.78% (141,598 votes) in the first round and 12.06% (149.417 votes) in the run-off with eight regional councillors elected. He has been a president of the FN group in the regional council during six years (2004–2010).
In the 2008 municipal elections, he led the FN list in Perpignan, polling 12.29% in the first round (4,543 votes) and 10.42% in the run-off (4,368 votes) with two municipal councillors elected. His result was one of the few good results for the FN, which suffered severe loses nationwide.
In the 2009 municipal by-election, he again led the FN list but lost his municipal seat in the first round (9.42%, 3,382 votes). Since June 2009, the FN is not represented in the municipal council of Perpignan. In order to take part in the run-off, a municipal list must cross the minimal threshold of 10% of the valid votes.
In the 2009 European elections, he led the FN list in the South-West France constituency. Polling 5.94% (155,806 votes), he was not elected as MEP.
In the 2010 regional elections, he led the departmental list in the Pyrénées-Orientales whereas France Jamet led the regional list in the Languedoc-Roussillon. Polling 13.64% (19,785 votes) in the first round, his list achieved 19.99% (30,581 votes) in the run-off with two councillors elected in the Pyrénées-Orientales. After having sat during twelve years in the regional council of Midi-Pyrénées, he has been a regional councillor in the Languedoc-Roussillon since March 2010.
On 14 March 2011, Louis Aliot and Mario Borghezio MEP accompanied Marine Le Pen MEP during her stay in Lampedusa island. On 15 March 2011, they together took part in an international press conference in Rome.
In the 2011 cantonal elections, he was the FN candidate in the urban canton of Perpignan-9. Polling 34.61% (1,083 votes), he won the first round by a large margin. Despite an increase of 11.63% (514 votes) in the second round, he was defeated by the Socialist candidate supported by the UMP.
During the 2012 presidential election, Aliot was the operational head of Marine Le Pen's campaign and one of her spokesmen. One of his most notable trips was to Israel in December 2011 to meet local politicians and French citizens to establish links.
He was, along with Florian Philippot, a spokesman for the party in the legislative elections. In the Pyrénées-Orientales' 1st constituency, he gathered 24.13% of votes in the first runoff, facing the candidates of the Union for a Popular Movement and the miscellaneous left, but he ended up in the third position with 23.24% in the second round; the candidate of the left won with 42.95%.Regional councillor of Languedoc-Roussillon: since 26 March 2010
Regional councillor of Midi-Pyrénées: 15 March 1998 – 21 March 2010 (leader of the FN group 2004–2010)
Municipal councillor of Perpignan: 23 March 2008 – 21 June 2009