Mr Robinson is set to become Ian Paisley's successor
Peter Robinson has been elected the new leader of the Democratic Unionist Party but it could be June before he becomes Northern Ireland's first minister.
The East Belfast MP, 59, will replace Ian Paisley while North Belfast MP Nigel Dodds will become deputy leader.
Mr Paisley will resign in May, triggering the removal of Martin McGuinness as deputy first minister.
The Sinn Fein minister will remain in position in a caretaker capacity until being renominated with Mr Robinson.
Mr McGuinness said he would work as constructively with Mr Robinson he has done in office with Mr Paisley.
"Now you're not going to get Chuckle Brothers, Part Two," he said.
"What you are going to get are serious-minded people hopefully taking serious decisions and I am going to stride and endeavour to bring to all of this the same sort of positive and constructive approach that I had during the time that Ian Paisley was there."
DUP MP Gregory Campbell said Peter Robinson would bring a new style of leadership.
Mr Robinson was the choice of the 36-strong DUP assembly group on Monday.
In a statement, the DUP grouping revealed the joint nomination was proposed by East Antrim MP Sammy Wilson and seconded by Stormont Environment Minister Arlene Foster.
Director of elections
Assembly members unanimously agreed the joint nomination which will go to the party's 120-member executive committee on Thursday for formal ratification.
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 Robinson becomes leader-designate until Mr Paisley officially stands down.
Mr Robinson has been an MP for almost 30 years. He has been the party's main tactician and its director of elections during a period which has seen it forge ahead of the rival Ulster Unionists.
As finance minister, he has played a key role in the executive.
The low point of a highly successful political career was his arrest in Monaghan following the "invasion of Clontibret" in the 1980s and critics still raise his involvement with the Ulster Resistance Movement.
He is about to succeed a man whom he called "the best leader Northern Ireland ever had".