[11] In October 2018, he left the PSD due to disputes with its leadership, set up a new party called Chega, and resigned his seat on Loures city council.

[12][13] Chega had been initially prevented from registering as a political party as some of the 8,000 signatures presented to the Constitutional Court included minors and police officers.

While the Socialist Party (PS) won the most seats, Chega gave support to a right-leaning government led by José Manuel Bolieiro of the PSD, in exchange for a review of the region's constitutional status.

[22] Ricardo Cabral Fernandes of Jacobin reflected that "The Azores are a small region — but this was a big step in the normalization of Chega, and a trial run for a similar solution at a national scale".

[23] Ventura ran for the mainly ceremonial role of President of Portugal in the 2021 election, coming third with 12% of the vote, marginally behind runner-up Ana Gomes of the PS.

[28] Portuguese political scientists credited Chega's advances to a protest vote against the two largest parties, and the result in the Algarve to the difficulty that locals face finding housing in the tourism-heavy region.

[37] The agenda of Chega is heavily focused on criminality issues, support for the police forces of the country, and the misuse of taxpayers' money in terms of corruption at the top, overstaffing in the civil service at the middle and undeserving welfare recipients at the bottom.

[43][44] Describing itself a "strong proponent of Western civilization", the party positions itself against "Islamist extremism" and proposes stronger border controls and a decrease of "mass and illegal immigration".

[51][52] The party advocates for a decrease of the tax incidence, considering the current system to be "brutal and aggressive to the ones who work and build wealth, taking away half of their incomes".

[64][65] In July 2020, Chega joined the European Identity and Democracy Party, where its allies included the National Rally (France), Lega (Italy) and the Alternative for Germany.

[57] Vote share in the Portuguese legislative elections Due to its anti-immigration, anti-Islam and populist stances,[68] Chega has been the target of its critics who underline the party's extreme views on various subjects, some of which include the negative comments regarding immigration and minorities, namely the Romani,[69] its opposition to certain aspects of the constitution,[70][71] its criticism of the judicial leniency regarding serious crimes,[72][73] and governmental over-expenditure with public services.

[74] The party has also been targeted by critics for reusing a slightly modified version of the motto of the Portuguese dictator António de Oliveira Salazar "Deus, Pátria, Família" (God, Fatherland, Family).

[77][78] The Global Project against Hate and Extremism (GPAHE), an American NGO specialising in the study of extremist movements, warned in a 2023 report that Chega is an "anti-immigrant, anti-women, anti-LGBT, anti-Roma, anti-Muslim and conspiratorial party".

[62][79] A subsequent investigatory article by GPAHE found evidence of "more extreme" members in the Chega Youth group, including "white supremacists, fans of former dictator Antonio Salazar, and fascist sympathizers" including the President of the Coimbra branch João Antunes, the leader of the Porto branch Francisco Araujo, and Vila Nova de Famalicão leader Joana Pinto Azevedo.