SP.A was part of the "purple" federal coalitions of Prime Minister Guy Verhofstadt from 12 July 1999 until 10 June 2007, which contained both the Flemish and Francophone liberal and social-democratic parties.

The party was briefly led by Caroline Gennez, after former president Steve Stevaert left to become governor of Limburg.

Unlike its Francophone counterpart, the Socialist Party (PS), SP.A was not a participant in the Leterme II Government.

In January 2009, the party had apparently changed its name to Socialists and Progressive Differently (Dutch: Socialisten en Progressieven Anders).

From 2009–2014, SP.A participated in the Flemish Government, in an uneasy coalition with the CD & V and the N-VA. From 2014 onwards, SP.A formed part of the opposition in Flanders, as the regional government reflected the Flemish component of the federal administration, consisting of coalition of the Open-VLD, CD & V and the N-VA.

The party strives to ensure that those who earn the most or own the greatest wealth also pay the highest taxes so that the government can meet the needs of people who are less fortunate.

It opposes cuts in social security and advocates investment, especially in education and health care.