Mr Robinson is MP for East Belfast
Peter Robinson has been confirmed as the next leader of the Democratic Unionist Party.
The unanimous decision of the party's assembly group to appoint Mr Robinson was ratified by its 120-member executive committee on Thursday night.
The meeting also saw North Belfast MP Nigel Dodds confirmed as deputy leader. Both appointments were again backed unanimously.
Ian Paisley is to resign as DUP leader and NI first minister in June.
Mr Robinson and Mr Dodds, in a joint statement, said they were "deeply honoured" to be given the responsibility to lead the party.
"We want to pay tribute to Dr Paisley and the stirling service which he has given," they said.
"The DUP and Northern Ireland owe a great debt of gratitude to Dr Paisley for his leadership over many decades.
"He has a unique ability and it would be foolish for anyone to try and mimic his style of leadership."
Ian Paisley, congratulating the new leadership, said: "There is great responsibility in leading the largest political party in Northern Ireland, but I have full confidence that the new leadership team will lead the DUP on to many successes in the future."
Mr Paisley has led the DUP since its formation in 1971. Mr Robinson has been deputy leader for 28 years, with one short break.
Mr Paisley's resignation will trigger the removal of Martin McGuinness as deputy first minister.
However, the Sinn Fein minister will remain in position in a caretaker capacity until being renominated with Mr Robinson.