The counting of votes continues, but Mattarella has already gathered the majority of 505 votes necessary for victory.
The election became possible after Italian Prime Minister Mario Draghi, followed by leaders of the country's ruling parties and regions, appealed to the 80-year-old Mattarella to accept the position despite his insistence that he was not interested in a second seven-year mandate.
Earlier on Saturday, Mattarella received a delegation of leaders of parliamentary factions, to whom he reportedly announced his readiness to again lead the country, "considering the situation," since the last seven rounds of voting failed to yield results.