In his first address to the nation, the 69-year-old former academic asked for patience.
U Htin was sworn in before the Union parliament, taking his oath in unison with his two vice presidents - former general U Myint Swe and ethnic Chin Christian Henry Van Thio.
Following the swearing in, his ministers, including National League for Democracy (NLD) leader who is barred by the constitution from the presidency, took their oaths, completing a 144-day transition period since it won general elections against the military last November.
President U Htin Kyaw in his address pledged his government would work towards establishing a constitution that would guarantee a federal democracy and the lifting up lives of the people.
"The new government will try with commitment to fulfill the people's long waited political desires. We need to be patient to reach our goals," the Myanmar times quoted him as saying.
He also said that his government would also strive for "national reconciliation" and achieving peace.
U Htin and his cabinet then moved to the presidential palace for a formal handover ceremony with outgoing president U Thein Sein.
The President and Vice Presidents pledged of being faithful to the people of the republic of the union of Myanmar.
NLD leader, Suu Kyi was seated to U Htin Kyaw's left as he rose in parliament to take the stage for the brief swearing-in.
It has been confirmed to parliament that she would hold four ministerial posts, including that of foreign minister.
Many wanted 70-year-old NLD leader to be the new president, but refusal from the refusal of the military to amend the constitution that bars her from the top post on the grounds that her sons are foreign nationals stopped her from securing the coveted post.
Questions remain if Suu Kyi could yet become president after amending section 59(f) of the charter over the five-year term of the new government.
Meanwhile, swearing in of other ministers is still in progress. (ANI)