The ANC's National Working Committee has decided on 70-year-old Job Mokgoro as the North West premier.
Mokgoro, who is the former director-general for the province, was picked during a special NWC meeting on Wednesday night.
The party was racing against time as the 30-day deadline to find a candidate to replace Supra Mahumapelo is on Friday. Mahumapelo went on "early retirement" last month.
The judge president of the North West High Court in Mahikeng had already called for a sitting of the legislature on Friday to fill the vacancy.
If the position is not filled within 30 days, the Constitution calls for the dissolution of the legislature, forcing an early election.
The ANC has struggled to agree on who should succeed Mahumapelo, who was pushing for an ally to replace him, while alliance partners the SACP, Cosatu and Sanco opposed his choice, demanding someone outside his circle.
Although Mokgoro is not part of the party's provincial executive or government, his appointment was seen as a "compromise", as he was not the first preference for alliance partners.
The ANC's highest decision making body, the National Executive Committee, failed to agree on a name when it held a special meeting on Monday, and instead referred final decision to the NWC.
Mokgoro is expected to be premier until the 2019 elections as President Cyril Ramaphosa placed the province under administration. It followed weeks of violent protests calling for Mahumapelo to step down.
A source said the NWC would still meet to decide on the fate of the Provincial Executive committee, as some members are implicated in the report by the inter-ministerial committee appointed by Ramaphosa to investigate the state of the province.
Mokgoro, who was married to Justice Yvonne Mokgoro, is known as a strict, honest and accountable person.
ANC Secretary General Ace Magashule is expected to make the formal announcement at 11:00.