Former Assembly member John McCallister has been appointed to the Human Rights Commission.
The ex-Ulster Unionist left to help establish NI21 as an alternative to what that party saw as green and orange-tinted politics in the North.
But he fell out with fellow founder Basil McCrea, resigned from the party and lost a contest for his South Down seat last year.
Graham Shields, former chief electoral officer for the North, was among other new commissioners named by Northern Ireland Secretary James Brokenshire on Wednesday.
Chief commissioner Les Allamby said: "The new commissioners join us at a crucial period. The protection and promotion of human rights is vital in these uncertain political times."
The six new part-time commissioners also include: Helen Ferguson, a former director, Helena Macormac, a lawyer, Paul Mageean, a director, and Edmond Rooney, a retired civil servant.
Mr McCallister's former party pledged to focus on its modernising vision of bolstering science and innovation and creating a shared Northern Ireland identity.
But the fledgling group imploded over whether to define itself as unionist ahead of the local government and European elections in 2014 and ended up winning only one council seat.