He's also an award-winning columnist for his work in Colombian newspaper, El Tiempo.
He joined the navy at 16 and has formerly been Defence Minister, Minister of Foreign Trade and Minister of Finance.
President Santos belongs to an influential political family. His great-uncle Eduardo Santos Montejo was the Colombian President from 1938 to 1942. His cousin Francisco Santos Calderon served as Vice President from 2002-2010. The Santos family also founded 'El Tiempo', one of Colombia's largest newspapers.
Colombian Civil War
Colombia has been at war since 1948 when violence broke out between military wings of the liberal and conservative parties.
The prolonged war saw the Colombian government, guerrilla groups, paramilitary forces, crime syndicates and Revolutionary Armed Forces of Colombia (FARC) fighting against each other.
The warring factions fought for varied reasons: protecting peasantry from the state, social justice, fighting threats from guerrilla groups etc.
1964 - 2016
Revolutionary Armed Forces of Colombia (FARC)
The FARC was founded in 1964 as a military-wing of the Communist party to continue the leftists' struggle.
Although mainly a peasant army of Marxist-Leninists, FARC has battled Colombian authorities and paramilitary-forces for decades.
Inspired by the Cuban revolution, it was labelled a terrorist organization by the US and the EU.
In September 2016, FARC executed a peace deal with the Colombian government.
The cost of conflict
The conflict resulted in the death of 220,000 Colombians and displacement of 6 million people. Although FARC fought for improved conditions for the poor but faced immense criticism for using child soldiers, attacking police stations, military posts and blowing up oil pipelines and bridges.
President Santos and FARC Peace Deal
In 1994, Santos was part of a team of negotiators to broker a peace-deal with FARC.
In 2006, as Defence minister he escalated the government's campaign against FARC and was responsible for their biggest setbacks.
Santos became President in 2010 and dedicated his presidency to ending the civil-war.
In 2012, negotiations with FARC began and concluded last month with the signing of a peace-deal.
FARC Leader on Peace Deal
Leader of FARC rebel group, Rodrigo Londono said, "We yearn that no Colombians will ever again have to take up arms to make their voices heard and their demands felt, as has been required of us."
FARC Peace Deal rejected in referendum
The peace-deal negotiated between the Colombian Government and FARC was dealt a fatal blow as voters rejected the referendum.
Of 13 million votes cast, 50.2% voted 'against' and 49.8% voted 'for' - the difference was a mere 54,000 votes.
Those who voted against thought the 'peace deal' was too lenient towards FARC rebels which allowed them to escape prison despite committing innumerable war crimes.
08 Oct 2016
Juan Manuel Santos wins the Nobel Peace Prize
The Colombian President, Juan Manuel Santos, won the Nobel Peace prize for 2016 on Friday, September 7.
He was awarded the Nobel Peace Prize for his unrelenting efforts to end a five-decade long civil war in Colombia which killed over 200,000.
President Santos signed a peace deal with FARC rebels last month, but in a surprise verdict, Colombians rejected it in a referendum.
Nobel Committee's trust in Juan Manuel Santos
The Nobel-Committee believed that despite the rejected-referendum, President Santos "brought the bloody conflict significantly closer to a peaceful solution." With respect to his commitment to work for peace, the Committee hoped "that the Peace Prize will give him strength to succeed in this demanding task."
10 Oct 2016
President Santos donates Nobel Peace prize award
Colombian President, Juan Santos, announced that he will be donating the Nobel Peace prize-money towards victims of Colombia's civil-war. The announcement came right after he partook in a religious ceremony held for the victims.
His decision was made after consultations with his family.
Santos will be dedicating the 8-million Swedish Krona or $925,000 award he received for his "resolute efforts" to end Colombia's civil-war.