The party was formed in 1994 by former members of the Parti libéral du Québec who left that party due to its reluctance to commit to Quebec sovereignty following the defeat of the Charlottetown Accord.
Initially, the party was led by former Liberal MNA Jean Allaire, but he resigned within a few months and was succeeded by former Liberal youth committee president Mario Dumont, who has retained the leadership to this day. Dumont won a seat in the Quebec National Assembly in that year's provincial election, the only adéquiste candidate to do so.
In the 1995 Quebec referendum, Dumont campaigned for the Yes side. However, in subsequent election campaigns he has promised a moratorium on the sovereignty question.
Although Dumont was an immensely popular leader, ADQ support always lagged behind his personal support. Dumont remained his party's only sitting MNA until 2002, when voter dissatisfaction with both the Parti Québécois government of Bernard Landry and the Liberal alternative presented by Jean Charest led the ADQ to an unexpected victory in a series of provincial byelections, bringing the party caucus to five members.
Suddenly the ADQ soared in popularity, leading the established parties in public opinion polling for the first time in its existence. However, the party's conservative platform was now subjected to increased scrutiny, and its support faltered once more.
In the 2003 Quebec election, the ADQ lost the four seats it had gained in byelections, but picked up three other seats previously held by the PQ, and pulled enough votes from the PQ to give the victory to Charest's Liberals. The party obtained 18 per cent of the popular vote in that election, its best result to date.