Nepal's parliament on Wednesday elected Prachanda, who led a decade-long insurgency that topped a feudal monarchy, as the Himalayan nation's new prime minister, a week after KP Oli stepped down to avoid a no-confidence motion.
Nepal has long been mired in political instability and Prachanda, 61, becomes its 24th prime minister since protests led to the establishment of a multi-party democracy in 1990.
He has served once before, after winning power in 2008.
Prachanda, whose real name in Pushpa Kamal Dahal, won 363 votes of the 573 votes cast in the 595-member parliament.
Lawmkers draped Buddhist prayer scarves around his neck after he was elected unopposed.
"I will work for national unity, to promote the interest of the country and its people," the bespectacled leader had told lawmakers earlier.
The return of Prachanda, who still uses his nom de guerre, which means "fierce", but has lost his former Robin Hood image, is unlikely to end the revolving-door politics that has sapped business confidence in one of the world's poorest countries.
"I don't think he will be stable," said Guna Raj Luitel, editor of the daily Nagarik.
"There is no agreement between parties on a basic agenda for the country. They have only agreed for convenience, and there is already a deal to change the prime minister after nine months."
Prachanda's confirmation became possible with the support of parliament's biggest party, the centrist Nepali Congress, and several smaller parties. The Maoists are the third biggest group in the legislature.
Under a widely reported power-sharing deal, Nepali Congress leader Sher Bahadur Deuba is expected to take over from Prachanda before Nepal holds a general election at the beginning of 2018.
Party officials have declined to comment. The two leaders make for a disparate combination.
Deuba headed the cabinet that offered a bounty of 5 million rupees ($50,000) for Prachanda in 2001, at the peak of the insurgency. Two years later, Maoist guerrillas shot up Deuba's convoy in west Nepal, but he escaped unhurt.
Frequent changes of government are blamed on politicians who are seen as selfish and power hungry, and who show little concern for the plight of Nepal's 28 million people. Nearly a quarter live on less than $2 a day.
Politics in Nepal, which has great potential to generate hydroelectric power, is closely watched by giant neighbors China and India as they vie for influence over the country that is home to Mount Everest and the birthplace of Lord Buddha.
In 2008, Prachanda visited China before India, breaking a tradition of new Nepali leaders making New Delhi their first foreign port of call.
On a March visit, Oli cosied up to China with a deal to use its ports for trading goods with third countries, ruffling feathers in India, which controls landlocked Nepal's main overland trade route.
India is blamed in Nepal for imposing a blockade on fuel and essential goods last year after its Madhesi minority protested against the first post-monarchy constitution. India denies the accusation.
Prachanda said his government would continue the pacts Oli signed with China and India.
The Madhesis, mostly southern plains dwellers with ties to India, say the charter weakens their position in the central government by dividing their homeland.
The new leader also faces a huge reconstruction effort after earthquakes that killed 9,000 people last year, besides overseeing settlement of war crimes cases against the Maoists and the security forces.