It achieved congressional representation shortly thereafter and played a leading role in the development of the Chilean labor movement.

Concern over the PCCh's success at building a strong electoral base, combined with the onset of the Cold War, led to its being outlawed in 1948 by a Radical government, a status it had to endure for almost a decade until 1958 when it was again legalized.

At the 2005 legislative election, 11 December 2005, the party won 5.1% of the popular vote, but as a result of Chile's binomial electoral rules, no seats.

The small but significant support of the PCCh is believed to have aided in the electoral victories of former socialist president Ricardo Lagos in the 2000 elections, and in the more recent victory of Chile's first female president, the socialist Michelle Bachelet in January 2006, both of whom won in competitive second round runoffs.

From 2013 to 2018, the PCCh was a member of New Majority (Spanish: Nueva Mayoría), a leftist coalition led by Michelle Bachelet.

[11] However, some of its leaders have also publicly condemned the human rights abuses that have taken place in Venezuela under the government of Nicolás Maduro.