Mr Díaz-Canel had been serving as first vice-president for the past five years.
Even though Mr Díaz-Canel was born after the revolution, he is a staunch ally of Raúl Castro and is not expected to make any radical changes. There was "no room in Cuba for those who strive for the restoration of capitalism" he said in his inaugural address.
'The Revolution continues its course'
He was elected by the members of the National Assembly, all 605 of whom were voted in in March after standing unopposed.
Mr Castro is expected to continue wielding considerable political influence in his role as the leader of Cuba's ruling Communist Party.
Cuba's new President, Miguel Díaz-Canel, entered the chamber alongside the outgoing president, Raúl Castro. The moment captured the image of political continuity the Cuban government has been keen to stress: an ordered handover of power from one generation to the next.
There was a small surprise, a single dissenting vote to Díaz-Canel's nomination as president, as he was confirmed by just 99.83% of the vote.
Still, he had the one and only ballot he really needed: Raúl Castro's.
In his inaugural speech, Mr Díaz-Canel said that his mandate was "to ensure the continuity of the Cuban revolution at a key historic moment" and assured the members of the National Assembly that "the revolution continues its course". He said that Cuba's foreign policy would remain "unaltered" and that any "necessary changes" would be decided by the Cuban people.
A large part of his speech was dedicated to praising his predecessor in office, to whom he said: "Cuba needs you." This prompted the more than 600 National Assembly members to rise to their feet and give the 86-year-old former leader a standing ovation.
Any changes Mr Díaz-Canel will bring in are likely to be gradual, slow-paced and in keeping with the reforms Raúl Castro introduced since he first took over power from his brother, Fidel.