Paolo Rondelli has been chosen as one of the small European country's two "captains regent".
San Marino has reportedly become the first country in the world to elect an openly LGBT+ head of state.
Paolo Rondelli has been chosen as one of the small European country's two "captains regent," who will lead San Marino for the next six months, alongside Oscar Mina.
The 58-year-old said on Facebook that he will "probably be the first head of state belonging to the LGBT community".
Marco Tonti -- head of the Arcigay association in Emilia-Romagna where San Marino is located -- hailed it as "a historic event".
"He is the first openly gay head of state and activist for the rights of the LGBT community," Tonti said.
"There are precedents among heads of government and ministers but this is a world-first for a head of state."
Luxembourg's Xavier Bettel and Serbia's Ana Brnabić are two current examples of LGBT prime ministers in Europe.
Several Italian politicians took part in the ceremony of the two Captains Regent on Friday, including Senator and LGBT activist Monica Cirinnà.
"Paolo [Rondelli] is a man of immense culture and great diplomatic and political experience," Cirinnà said on Facebook.
"He fought for the rights of women and LGBT+ people, in San Marino and not only," she added.
"It’s a historic day, that fills me with joy and pride, because Paolo Rondelli will be the first head of the State belonging to the LGBT+ community, not only in San Marino but in the world."
San Marino -- a microstate of just 34,000 people -- is landlocked within the Italian region of Emilia Romagna.
The country's two "captains regent" preside over the nations' Grand General Council, the legislative body that elects them every six months.