Although it explicitly supported Northern Ireland staying part of the United Kingdom (i.e. unionism), it planned to designate as "other" rather than "unionist" in future Stormont elections.

The party had two MLAs in the Northern Ireland Assembly and a single councillor on Lisburn and Castlereagh City Council.

[5] The party was officially founded on 6 June 2013 with a livestreamed press conference in the Metropolitan Arts Centre in Belfast.

The party also attracted criticism in its first week following comments made by Basil McCrea on the topic when an interviewer asked about polygamous marriage.

[17] However, NI21's deputy leader, John McCallister, condemned the move, saying the decision was not properly debated and showed how "dysfunctional" NI21 had become.

However, McCallister was publicly defended by the party's youth wing, which criticised a "lack of respect shown towards our deputy leader".

[19] As the crisis developed, McCallister told the public that the internal rift was due to an external investigation into McCrea,[20] as a former party worker had made allegations of sexual misconduct against him.

[21] Tina McKenzie, the European parliamentary candidate and former chairperson, resigned from the party executive half an hour before voting ended on election day.