Early groups of "Olivists" were formed in 1995–1996, during the campaign for the 1996 general election, by close supporters of Prodi who were not members of any party of The Olive Tree coalition, like Prodi himself. "Clubs for Prodi" and the "Citizens for The Olive Tree" association were organised. Although most Olivists took part to the campaign only as activists, some were elected with the Populars for Prodi list, whose main constituent parties were the Christian-democratic Italian People's Party (PPI) and the social-liberal Democratic Union (UD). The Olive Tree won the election, the PPI–UD joint list obtained 6.8% of the vote, and Prodi was sworn in as Prime Minister, at the head of the Prodi I Cabinet.
In December 1999 the party joined D'Alema II Cabinet with four ministers: Maccanico as minister of Institutional Reforms, Enzo Bianco (who had missed the election as MEP for a few votes) minister of the Interior, Willer Bordon ministers of Public Works, and Paolo De Castro minister of Agriculture. Of these, all but the latter would be confirmed in Amato II Cabinet, which was formed in April 2000, after the coalition's defeat in the regional elections.
In early 2000 Parisi asked the Democrats of the Left, then led by Walter Veltroni, to dissolve into a new "Democratic Party". The proposal was not received, thus in October 2000 The Democrats agreed with the PPI, Italian Renewal and the Union of Democrats for Europe to form a joint list for the 2001 general election, under the leadership of Rutelli, who was also The Olive Tree's "candidate for Prime Minister". The list, which gained a considerable success (14.5%), was transformed into a party in March 2002 under the name of Democracy is Freedom – The Daisy.[2] This party, led by Rutelli, would be eventually merged into the Democratic Party in October 2007.[3]
The party was fervently "Olivist" (that is to say interested in the creation of a more united centre-left and, possibly, a joint centre-left party) and Europeanist, while also favouring the establishment of a two-party system. The name and symbol of the party were a direct reference to the Democratic Party of the United States.[3]