The party was founded by Siim Kallas, then-President of the Bank of Estonia, as a split from National Coalition Party Pro Patria. As the Reform Party has participated in most of the government coalitions in Estonia since the mid-1990s, its influence has been significant, especially regarding Estonia's free market and low taxes policies. The party has been a full member of Liberal International since 1996, having been an observer member between 1994–1996, and a full member of the Alliance of Liberals and Democrats for Europe (ALDE). The founder and the first chairman of the Reform Party, Siim Kallas, was a Commissioner of the European Commission between 2004 and 2014. He was also one of the five Vice Presidents of the Barroso Commission. Reform Party leaders Siim Kallas, Taavi Rõivas, Andrus Ansip and Kaja Kallas have all served as Estonian Prime Minister.