What you need to know:
- From humble beginnings, the multi-millionaire cast himself as a champion for the downtrodden during his campaign, vowing to create jobs and tackle a cost-of-living crisis.
William Ruto will be sworn in as Kenya's president on today after narrowly winning the coveted job in a bitterly fought but largely peaceful election.
About 20 heads of state and thousands of spectators are expected to attend his inauguration at a Nairobi stadium.
A notoriously ambitious politician who has been deputy president since 2013, Ruto beat his rival Raila Odinga -- who had been backed by outgoing president Uhuru Kenyatta -- by less than two percentage points.
He now faces a daunting task to steer a polarised country gripped by a cost-of-living crisis and punishing drought, say analysts.
The 55-year-old rags-to-riches businessman who once sold chickens on the roadside will become just the fifth president in Kenya's post-independence history.
By law, Ruto must take the oath of office by 2:00 pm (1100 GMT) on Tuesday, five weeks to the day since the August 9 election.
His rise to State House has been closely watched by the international community, which depends on Kenya as a reliable and stable democratic partner in a turbulent region.
Foreign allies and independent observers praised the conduct of the vote, which was largely peaceful and free of the violence that has marred past elections in the country of 50 million people.
Ruto won by only around 200,000 votes out of 14 million cast but the Supreme Court on September 5 upheld his victory, dismissing claims by his opponents of fraud and mismanagement.
- 'Hand of brotherhood' -
Outgoing head of state Kenyatta, who in a stunning turn of events had backed his longtime archrival Odinga in the election race, has promised a smooth transfer of power.
Kenyatta finally shook hands with Ruto at a meeting at the presidential residence on Monday after pointedly failing to publicly congratulate his deputy for several weeks.
Ruto has struck a conciliatory tone, extending a "hand of brotherhood" to his rivals and their supporters.
"We are not enemies. We are Kenyans," Ruto said after the court's decision.
But observers say he faces a tough assignment building goodwill after a divisive and expensive political campaign that lasted well over a year and was peppered with acrimony and personal slander.
"This is the time to close ranks, embrace opponents and help forge a united front devoid of cheap political competition," Kenyan newspaper The Standard wrote in a September 11 editorial.
Many ordinary Kenyans stayed away from the ballot box, with disillusionment particularly among the youth and economic hardship blamed for the low turnout.
The East African political and economic powerhouse is reeling from a once-in-a-generation drought and inflation is at five-year highs.
Ruto said Sunday that Kenya was "in a deep economic hole" and repeated his pledge to lower the cost of living as a priority upon taking office.
From humble beginnings, the multi-millionaire cast himself as a champion for the downtrodden during his campaign, vowing to create jobs and tackle a cost-of-living crisis.
Among his ambitious promises was the creation of a 50-billion shilling ($415 million) "hustler fund" to provide loans to small businesses, and a commitment to bring down prices for fuel, grain and fertiliser.
- Generous send-off -
The task to turn around the economic fortunes of the country may, however, not be easy, the International Crisis Group (ICG) think tank said, urging Ruto to quickly address the challenges.
"The 2022 Kenyan elections may have been a success... For Ruto, however, given sky-high popular expectations and an economy in dire straits, governing may well prove tougher than campaigning," it said in a statement.
Ruto's inauguration marks the end of Kenyatta's nearly decade in power, and one of the rare occasions his powerful family has not been at the apex of Kenyan politics.
Already one of Kenya's wealthiest citizens, the outgoing president will receive a generous send-off under Kenya's constitution as he leaves office having served two terms, the maximum allowed by law.
The 60-year-old will receive a tax-free lump sum of $324,000 and more than $600,000 in allowances every year.
Kenyatta, the son of Kenya's first president Jomo Kenyatta, will also have access to fully furnished offices, dozens of aides, VIP security and new cars of his choice, replaced every three years.