The party was founded in 1988, named simply Fidesz (Fiatal Demokraták Szövetsége, meaning the Alliance of Young Democrats), originally as a youthful libertarian, anti-communist party. Fidesz was founded by young democrats, mainly students, who were persecuted by the communist party and had to meet in small, clandestine groups.

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After its disappointing result in the 1994 elections, Fidesz changed its political position from liberal to conservative.[11][14] In 1995, it added "Hungarian Civic Party" (Magyar Polgári Párt) to its shortened name. The conservative turn caused a severe split in the membership. Péter Molnár left the party, as well as Gábor Fodor and Klára Ungár, who joined the liberal Alliance of Free Democrats.

Fidesz gained power in 1998 under leader and Prime Minister Viktor Orbán, who governed Hungary in coalition with the smaller Hungarian Democratic Forum and the Independent Smallholders' Party. In 2000, Fidesz joined the European People's Party and had its membership in the Liberal International terminated.[14]

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In the 2009 European Parliament election, Fidesz won a landslide victory, gaining 56.36% of the vote and 14 of Hungary's 22 seats. This predicted a landslide in the 2010 parliamentary elections, where they won the outright majority in the first round on April 11, with the Fidesz-KDNP alliance winning 206 seats, including 119 individual seats. In the final result, they won 263 seats, of which 173 are individual seats.[18] Fidesz holds 227 of these seats, giving it an outright majority in the National Assembly by itself.

After winning 53% of the popular vote, which translated into a supermajority of 68% of parliamentary seats, giving Fidesz sufficient power to revise or replace the constitution, the party embarked on an extraordinary project of passing over 200 laws and drafting and adopting a new constitution—since followed by nearly 2000 amendments.

The new constitution has been widely criticized[19][20][21][22][23][24] by the Venice Commission for Democracy through Law,[25] the Council of Europe, the European Parliament[26] and the United States[27] for gathering too much power in the hands of the ruling party, Fidesz, for limiting oversight of the new constitution by the Constitutional Court of Hungary, and for removing democratic checks and balances in various areas, including the ordinary judiciary,[28] supervision of elections and the media.