Devolved government returned as MLAs gathered at Parliament Buildings for a sitting where ministers were appointed to a powersharing executive, bringing an end to the impasse.
Michelle O’Neill became the first nationalist first minister.
Sinn Fein's vice president hailed Saturday as a "historic day."
“It is about the future. It is about working together to deliver for workers and families, and creating new and exciting opportunities that ensure our children and grandchildren can achieve their dreams and ambitions in life," Ms O'Neill added.
The DUP, the largest unionist party in the region, agreed to drop its two-year Stormont blockade in exchange for government measures aimed at addressing its concerns about post-Brexit trading arrangements that created economic barriers between Northern Ireland and the rest of the UK.