What you need to know:
- Protest politics have kept Mr Odinga relevant and impossible to ignore as champion of the angry and resentful poor and dispossessed through decades of struggle since launch of the multiparty campaign more than three decades ago.
Raila Amolo Odinga has spent most of his adult life in politics, including eight years in prison as a pro-democracy campaigner, but despite five attempts has never achieved his goal of becoming Kenya's president.
The 77-year-old on Monday lost his fifth bid for the top job as the Supreme Court dismissed his objections to the outcome of the August 9 poll, which awarded a narrow victory to Deputy President William Ruto.
Odinga has long cast himself as an anti-establishment firebrand, despite belonging to one of Kenya's top political dynasties.
But his decision to strike an alliance with his arch-rival, President Uhuru Kenyatta, took the shine off his brand, enabling Ruto to paint himself as the champion for ordinary Kenyans struggling to survive in a country dominated by elites.
The Kenyatta and Odinga families have cast a long shadow over Kenyan politics since the country won independence from colonial ruler Britain in 1963.
Uhuru Kenyatta's father Jomo was the East African nation's first president, while his rival Jaramogi Oginga Odinga -- Raila's father -- served as vice president.
Born on January 7, 1945, Odinga spent his early years in politics either in jail or in exile, fighting for democracy during the autocratic rule of president Daniel arap Moi.
A member of the Luo tribe, he entered parliament in 1992 and ran unsuccessfully for the presidency in 1997, 2007, 2013, 2017 and 2022, claiming to have been cheated of victory in the last four elections.
The 2007 polls in particular -- which many independent observers also considered deeply flawed -- shocked Kenyan politics, unleashing ethnic violence that pitted the Luo and Kalenjin tribes against the Kikuyu community, costing more than 1,100 lives.
Few therefore expected Odinga and Kenyatta -- a Kikuyu -- to shake hands and draw a line under decades of vitriol in March 2018, effectively leaving Kenya without an opposition.
Kenyatta's endorsement of Odinga came at the expense of Ruto, who found himself frozen out as the erstwhile foes drew closer.
But the rapprochement also came laden with risks for Odinga. Ruto, 55, was able to position himself as a spokesman for the "hustlers" trying to make ends meet in a country ruled by "dynasties".
Even as Odinga attempted to pull off a complex balancing act, keeping his base happy while trying to attract Kikuyu voters, he remained a polarising candidate.
While his supporters consider Odinga a much-needed social reformer, detractors see him as a rabble-rouser unafraid to play the tribal card.
A charismatic speaker, he has a reputation for being stubborn and sometimes short-tempered.
In the eyes of some observers, his crowd-pleasing skills have diminished in recent years, attributed to advancing age and ill health.
With his speech notes in hand, he often stumbles and labours over his words -- especially in English. Speaking off-the-cuff in his native Swahili, however, he retains the ability to inspire.
'Win some, lose some'
Passionate about reggae, he had adopted South African star Lucky Dube's song "Nobody Can Stop Reggae" as an unofficial motto for his campaign in recent years.
Many observers believe the one-time prime minister will not run for the presidency a sixth time, but he has kept his cards close to his chest.
An Arsenal fan, he credits his love of football for helping him develop a philosophical attitude towards the rough-and-tumble world of politics.
"You lose some, you win some. It is painful but that is the way to perfection," he said in an interview with AFP last year.
Raised an Anglican, he later converted to evangelicalism and was baptised in a Nairobi swimming pool by a self-proclaimed prophet in 2009.
The Bible even crept into Odinga's 2017 campaign with his repeated promise to lead his followers to Canaan, the mythical "promised land".
He studied engineering in communist former East Germany and named his eldest son Fidel, who died in 2015, after the Cuban revolutionary.
Although not as wealthy as Kenyatta or Ruto, Odinga sits at the head of a business empire with stakes in energy companies.
Married to his wife Ida for almost half a century, Odinga has three surviving children and five grandchildren.