Edwin Poots has been elected as the new leader of the Democratic Unionist Party after a knife edge vote, party chair Lord Morrow has announced.
The Lagan Valley MLA won by a razor-thin 19 votes to 17 in the poll carried out within the party's 36-strong electoral college.
Mrs Foster was ousted after an internal heave by party colleagues unhappy with her leadership and will step down from that role on May 28, and as Stormont First Minister at the end of June.
Mr Poots will be leader designate until Mrs Foster formally stands down. His election will now go to the party executive for ratification.
The DUP politicians eligible to vote comprised the party's eight MPs and 28 Assembly members.
The voting by way of secret ballot took place at the party headquarters in east Belfast through Friday afternoon.
Ahead of the vote, Sir Jeffrey and Mr Poots made final pitches for support in a virtual hustings event on Friday morning.
Paula Bradley was elected the party's new deputy leader. She defeated Gregory Campbell by 18 votes to 16.