Though he was sworn-in, few hours after his narrow victory was announced, Saturday's ceremony marked the official transfer of power from outgoing President Ernest Bai Koroma to incoming President Julius Maada Bio.
Maada Bio's campaign promise to revive the economy and fight poverty resonated with ordinary Sierra Leoneans, many of whom queued for hours to attend the inauguration.
"I am aware that we have been elected on a ticket for change which fuels immediate expectations to deliver not only on the basic administrative services but also to change the lives of the people of this country," President Bio said to the mammoth crowd.
Sierra Leone is facing a years-long slump in commodities prices that has held up development of large-scale iron ore mining projects. And an Ebola crisis paralyzed and isolated the country in 2014 and 2015.
The economy contracted by more than 20 percent in 2015 and is yet to fully recover.