The Co-operative Commonwealth Federation was formed in 1932 and ran its first candidates in the 1933 general election but failed to win any electoral representation.

In the 1939 Cape Breton Centre, by-election Douglas MacDonald won the CCF's first seat in the legislature.

In 1941, the future Canadian Labour Congress (CLC) president Donald MacDonald was elected from the Cape Breton South constituency.

He was joined by Douglas Neil Brodie, who was elected in Cape Breton East constituency, bringing the CCF up to a total of three MLAs.

CCFers Cunningham and fellow Cape Bretoner Michael James MacDonald were the only opposition MLAs elected.

Cunningham and MacDonald were re-elected in 1949 but were reduced to third party status behind Robert Stanfield's Progressive Conservatives.

The NDP would not win another until Jeremy Akerman became party leader and won the riding of Cape Breton East in the 1970 election.

[11] Following increasingly bloody internal battles Akerman resigned and the NDP lost all four Cape Breton seats in the following election.

The Liberals formed a minority government with the support of 14 Progressive Conservatives (Tories), the latter who had also improved their standings.

But with 11 seats in the legislature with 29.9% of the vote, it edged out the Liberals and were able to retain "Official Opposition" status when the PCs formed a majority government under John Hamm.

The 2003 election resulted in a PC minority government while the NDP maintained Official Opposition status under new leader Darrell Dexter.

Two members of the party's caucus, Gordie Gosse and Frank Corbett resigned for personal reasons in April 2015, triggering two of three provincial by-elections which were held on July 14.

Since that election, three NDP MLAs resigned: Dave Wilson,[16] Lenore Zann,[17] and Tammy Martin.

[20] He was succeeded by Claudia Chender on June 25, 2022 at a leadership convention held in Dartmouth to confirm her as leader.

The youth wing was partially responsible for the election of Jeremy Akerman, as leader, at the 1968 Leadership Convention.

At this time the youth wing was quite moderate, encouraging the main party to focus on government and embrace mainstream values such as fiscal responsibility, "one member one vote" and banning corporate and union donations.

The NPYM made a positive impact at the 2001 NSNDP convention pushing the party to adopt a “one member one vote” style of electing its leader, successfully distributed home-made buttons to satire an organized attempt to shame members of the NDP caucus who did not support former leader Helen MacDonald and gaining over 2/3 support from convention delegates for their name change.