In an interview with the Nobel Foundation, the Colombian leader accepted the prestigious award in the name of his people, and insisted a peace agreement was possible despite the nation's shock rejection of a historic deal he reached last month with the communist FARC rebels.
"I receive this award in their name -- the Colombian people who have suffered so much... and especially the millions of victims that have suffered with this war that we are on the verge of ending," he told the Nobel Foundation in a telephone interview.
"The message is that we have to persevere and reach the end of this war. We are very, very close, we just need to push a bit further," he said.
Santos expressed a similar sentiment on Twitter, writing that "this honourable distinction is not for me, it's for all victims of the conflict. Together we will win the most important prize of all: PEACE."
Winning the prize will be a huge encouragement to the Colombian people to continue their search for peace, despite their rejection of the terms of the deal inked just 11 days ago with FARC guerrilla leader Timoleon "Timochenko" Jimenez.
"This is going to be a great stimulus to reach that end and to start the construction of peace in Colombia," he said.
"I think this is the moment. The conditions are right."
The announcement that Santos had won took Nobel watchers by surprise, but the Norwegian committee said the aim was to encourage Colombia to end its 52-year civil war, warning that peace efforts were now in "real danger" of collapse.
And it dismissed claims that the award did not respect the democratic choice of voters who took part in the referendum.
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"We, of course, respect the democratic process and the democratic vote of the Colombian people but the people of Colombia did not say no to peace... they said no to this particular agreement," committee chairwoman Kaci Kullmann Five told reporters.
"And there is now a process of opening up a dialogue... to try to move the process forward. This is extremely important to avoid civil war flaring up again."
The Colombia conflict has killed more than 260,000 people and left 45,000 missing over five decades, drawing in several leftist guerrilla groups, right-wing paramilitaries and drug gangs.
More on the awarding of the 2016 Nobel Peace Prize to Juan Manuel Santos can be found here.