Milanovic took the presidential oath before Constitutional Court President Miroslav Separovic, after the national anthem "Our Beautiful Homeland" was performed by singer Josipa Lisac accompanied by pianist Zvjezdan Ruzic, and a minute's silence was observed for the fallen in the 1991-1995 Homeland War.
He was sworn in for a term of five years and began his inaugural speech. The first working day of the new president begins on Wednesday.
Presidential campaign director Orsat Miljenic will be the president's chief of staff, while the campaign's spokesman, Nikola Jelic, will be spokesman for the President's Office.
President Zoran Milanovic said in his inaugural address on Tuesday that elections are a way of reaching a peaceful compromise between the opposed wishes of different people, and that he will play a constructive role as President.
Addressing the inauguration ceremony, Milanovic said that the truth and voters' desire should be kept apart and that elections are not the way to find the truth but to reach a peaceful compromise between the opposed wishes of different people.
"It seems to me that there is only one right way, and that is full and active support by the government to academic and scientific independence and independence of the judiciary and media. That's the strongest defence against tyranny, tyranny of any kind," he said.
The scientific community, judiciary and media must work incessantly on perfecting the anti-corruption mechanisms. Protection and promotion of the independence of the judiciary, media and science are the most important constitutional responsibilities of the President of the Republic in ensuring the stability of government, Milanovic said.
He stressed that he is not going to be a corrective, but a constructive factor in areas of direct competence or co-competence of the President of the Republic, adding that this arises from the spirit of the Constitution.