“The former vice president, who had been out of the country after he was sacked from both party and government, will… replace comrade Robert Mugabe who resigned,” the state-run ZBC news site said on Wednesday.
Nicknamed “Ngwena” (The Crocodile) because of his fearsome power and ruthlessness, 75-year-old Mr Mnangagwa had appeared to have been outfoxed by Mr Mugabe’s wife, Mrs Grace Mugabe.
The first lady, who is 41 years younger than her husband, lobbied the veteran head of state to ditch his vice president, a long-serving lieutenant, to further her own political ambitions.
But Mr Mnangagwa has close ties with the military, which was alarmed at Mrs Mugabe’s rise, and the generals intervened.
It was the climax of a long feud between Mrs Mugabe and Mr Mnangagwa to be in pole position to replace the ailing leader when he died or retired.
Mr Mnangagwa – a long-time party loyalist and hardliner who, say some, could prove as authoritarian as Mr Mugabe – initially fled to South Africa after his sacking.
But the dramatic seizure of power by the military returned him to centre-stage.
On Sunday, Mr Mnangagwa was named president of the ruling ZANU-PF party in place of Mr Mugabe.
That put him one step away from the top job as Mr Mugabe was told to quit or be forced from office.
In the early days after independence from Britain in 1980, Mr Mugabe made Mr Mnangagwa – who was then a young trainee lawyer – minister for national security.
Mr Mnangagwa thereafter occupied a host of cabinet positions, but relations between him and his political mentor were not always cosy, and the younger man was no stranger to presidential purges.
In 2004 he lost his post as the secretary for administration in the party after being accused of openly angling for the post of vice president.