Lourenco leads the People's Movement for the Liberation of Angola (MPLA) party, which first came to power in 1975.
The 68-year-old is widely expected to secure a new mandate in a national vote on August 24 that analysts believe will be the tightest in more than 20 years.
He succeeded long-time ruler Jose Eduardo dos Santos in 2017 -- culminating a decades-long political career rich in twist and turns.
Upon taking office he promised sweeping reforms and a crackdown on corruption.
But observers say support for the Soviet-educated former general has faded as the oil-rich country grapples with soaring poverty and inflation.
"MPLA's popularity is low especially among the urban public," said Borges Nhamirre at the Institute for Security Studies, a Pretoria-based think tank.
Lourenco "promised more transparency, less corruption and inclusive governance" but "now his governance is seen as authoritarian," he said.
After winning the 2017 elections with 61 percent of the vote, Lourenco quickly turned on the former leader, Jose Eduardo dos Santos, starting an anti-corruption drive to recoup the billions allegedly embezzled by dos Santos' family.
Having inherited an oil-dependent economy deep in recession, he also launched an ambitious reform plan to differentiate revenue streams and privatise state-owned firms.
"The problem is that hasn't trickled down for most of the population," said Marisa Lourenco, an independent political analyst based in Johannesburg.
Dos Santos's death in Spain in July added to the president's woes, triggering a public spat with the veteran revolutionary leader's children -- several of whom face an array of corruption investigations.
Yet the change in tack from the previous regime has won praise abroad where the president's standing remains good.
Lourenco has become the go-to mediator in Africa's Great Lakes region, from tackling crisis in the Central Africa Republic to brokering tension-easing talks between the Democratic Republic of Congo and Rwanda.
Back home, he is promising to build better infrastructures at home, including new hospitals and transport links if given a second term.