Francisco Guterres has fought for his country before.
The former guerilla fighter was a key leader in Timor-Leste's struggle for independence.
Now he is ready to fight again.
"Even though I spent over 24 years in the jungle fighting for my country, I considered that I didn't do much, or it wasn't completed. There's lots more to be done."
The new president takes the helm of a country that has made tremendous improvements to development since independence in 2002.
But he inherits a dilemma: an economy heavily reliant on oil and gas, with reserves that may run out within a decade.
Mr Guterres says he plans to continue a strategy of spending on infrastructure in the hope of attracting tourism and foreign investment.
"First, Timor-Leste is prepared for this. But we need to have more investment in infrastructure."
In the western enclave of Oecusse, construction dominates the rural landscape.
A vision to reform the poorest district in the country to a modern city ready for investors is coming to life.
Mari Alkatiri is a former prime minister of Timor-Leste and the current head of the Oecusse Special Economic Zone.
"The triangle for development is financial centre, tourism and agribusiness industries."
Bridges, roads, a new airport and a new irrigation system are under construction, spurred by a $400 million investment of public money.
Across the road from Reuban Landos's small rural village on the edge of a paddy field, a new 56-room hotel is being built.
He says he welcomes it.
"It's good for Oecusse Timorese, because they didn't have the work and, now, they all have work."
But many in Oecusse and across the country still do not have access to running water or sanitation.
Charlie Scheiner, a researcher with the Dili-based analysts L'ao Hamutuk, says the government's infrastructure priorities are wrong.
He suggests there should be more spending on areas such as health care, education and child nutrition.
"This is a very young country, and it has tremendous challenges. And so we think that investing in things that will make people's lives better in the short term will also help economic development in the long term."
The new president says all development spending is well-considered.
"Just by way of an example, we don't withdraw money from the petroleum fund to go shopping for vegetables for us to share."
But what he does prioritise from here will be critical to the young nation's future - at a time of major economic change.
Rhiannon Elston travelled to Dili at the invitation of the Timor-Leste government.