But his quest to parlay fragile detente with the West into financial infusions to rebuild Iran's oil-based economy has been slowed by investors' fears of pre-existing USA sanctions and suspicions among powerful hardline acolytes of Supreme Leader Ayatollah Ali Khamenei of any rise in Western influence.
Within two weeks following the official appointment, the president has to submit a proposed list of ministers to parliament for approval.
Symbolizing the endorsement, Khamenei handed over the presidential mandate to Rouhani.
Addressing the ceremony, the Leader hailed the election process as the symbol of democracy in post-Revolution Iran. Javdanfar said the new USA sanctions on Iran signed by Trump into law on Wednesday, along with measures against Russian Federation and North Korea would likely deter foreign investors and so undermine Rouhani's efforts to boost the economy.
The law also imposed new sanctions on Russian Federation and North Korea.
"We face sanctions. Of course, sanctions create problems for the country; due to sanctions, however, we opened our eyes to our own strengths; today, despite the enemies' desire, we are powerful", Khamenei underscored. "We used all the enmities to our own benefit".
Rouhani stuck to an upbeat outlook in his speech.
The American Israel Public Relations Committee had lobbied for the sanctions.
Another priority is job creation which is a prerequisit for poverty alleviation, Rouhani emphasized; "in this way, we need more investment and access to advanced technologies to creat moe jobs".
Iran paid the price for its independence and will stand against enemy attempts to isolate the nation, he added, stressing, "We will never accept isolation".
"Transition from the most hard sanctions was achieved through a combination of the power of diplomacy and deterrent defensive power", said Rouhani.
"The main objective of the United States in implementing the sanctions against Iran is to destroy the JCPOA", Deputy Foreign Minister Sayed Abbas Araqchi said, referring to the Joint Comprehensive Plan of Action, the deal engineered between Iran and the five permanent members of the UN Security Council, alongside Germany and the European Union.
He was referring to the deal, officially called the Joint Comprehensive Plan of Action, by its acronym.
Rouhani further pledged to take necessary measures to elevate Iran's position and have effective interactions with the world based the country's Constitution.
The inauguration ceremony is expected to see a record turnout, with delegations from over 100 countries taking part in the event.