Win Myint on Friday was sworn-in as the new President of Myanmar, two days after he was elected by Parliament to replace Htin Kyaw, who resigned last week over health concerns.
He was elected after defeating two other candidates on Wednesday,
High-level officials, including State Counsellor Aung San Suu Kyi, attended the swearing in ceremony.
Myint, 66, was a former political prisoner jailed under the last military junta.
Ruling party National League for Democracy (NLD) veteran, Myint is one of the the small circle of collaborators and trusted men of Suu Kyi’s.
He replaces Htin Kyaw, who resigned on March 21 after the government revealed the former president, 71, had travelled abroad several times to undergo medical treatment.
Although the constitution grants broad powers to the head of state, Suu Kyi is expected to continue in her important role as State Counsellor.
The Nobel Peace laureate was given this post as she was not eligible for the presidency due to a constitutional rule that vetoes candidates with foreign relatives, in her case two children with British passports.
Apart from the new president, the other two candidates also took office as vice presidents.
The last military junta was dissolved in 2011 and passed power to a civilian government formed by former generals, which was later replaced by the NLD.
The Myanmar Constitution reserves broad powers for the armed forces, including a quarter of Parliament seats and key ministries such as Interior, Defence and Borders.