Sharaa, in a speech at parliament in Damascus, told MPs to "make this council a model of responsibility and competence" and described it as "a platform for truth and justice".
"Syria is writing a glorious history that reflects its heroism and we face the responsibility of building both the nation and the individual," he said.
The parliament has been seen as a test of Sharaa's pledge to build an inclusive new order in Syria, which was run by the autocratic Assad family for decades and had a legislative chamber that was seen as a rubber stamp.
Under the country's interim governing arrangements, two-thirds of the members of the 210-seat chamber were chosen last year by regional electoral colleges while Sharaa named the remaining third on July 1.
Officials have said this system was necessary because years of war had left millions displaced and made it impossible to rely on accurate population records or voter rolls.
Critics say it gave the executive branch extensive control over the selection process.
Sharaa has said he supports holding general elections once infrastructure and documentation allow.
A temporary constitutional declaration introduced in 2025 granted parliament limited authorities, and there is no requirement for the government to win a parliamentary vote of confidence.
The People's Assembly can propose and approve laws.
It has a 30-month term that is renewable, and it assumes legislative authority until a permanent constitution is adopted and elections are organised.
Abdel Halim al-Awak, a member of the committee that drafted the constitutional declaration, was elected speaker with 99 votes.
Awak, who is from northeastern Hassakeh province, served as a judge in the Justice Ministry for a decade, according to Syria's state-run SANA news agency.
Reports said he was among many Syrian officials who defected from Assad's government in the early days of the uprising and left for Turkey.
Sharaa has said the parliament will be tasked with forming a committee to draft a new constitution.
A former jihadist militant, Sharaa has reshaped Syria since toppling Assad, building close ties with the United States and European countries and vowing a new era of freedoms, although his first year in power was jolted by several bouts of violence pitting pro-government fighters against members of minority groups.
The chamber has 21 female MPs - 15 of whom were among those nominated by Sharaa, who severed ties with al-Qaeda in 2016.
Authorities have not issued a breakdown of how many MPs hail from ethnic and religious minorities.
Unofficial tallies have shown that 10 of the seats chosen last year went to members of religious and ethnic minorities, including Kurds, Christians and Alawites - the sect to which Assad belongs.
Four of the seats are vacant because one MP died while three others reserved for the predominantly Druze province of Sweida have yet to be filled.
Authorities have said the selection of MPs for Sweida has been postponed until "conditions become suitable".
The area has remained outside state control since government forces and allied fighters clashed with Druze there last July, with about 1700 people killed, according to the United Nations.
with AP
