Addressing heads of diplomatic missions in Croatia in his office, Milanovic said that he did not see the EU as a "project", which he called a technical term, but as Croatia's "destiny" and "the only smart path."
He noted that he was aware of the shortcomings of some European institutions but that this was not "systemic criticism" as there is no alternative to EU membership.
As for the EU's limitations, he pointed to "the European Commission's need to flourish and grow in terms of influence, just like any bureaucracy."
"But those are all challenges one can normally live with," he added in his address, which he delivered in Croatian.
Too strong embrace by EU can be like boa's grip
As Croatia's prime minister in 2015, Milanovic supported a plan by then British Prime Minister David Cameron to reduce the EC's powers.
"I have never been a proponent of an ever-expanding and ever-closer EU. It means more bureaucracy in the EC," Milanovic said at the time after meeting with Cameron, whom he mentioned in his address today.
PM Cameron would get an anxiety attack when hearing the term "ever-closer Union", said Milanovic.
"At one moment, it is necessary to say where the limits of integration are because too strong an embrace can cause constriction," Milanovic said, comparing it to a boa constrictor's grip.
He stressed that "a lot of people" in Europe believe that the EU is invading their personal space.
Underestimating these views has resulted in Brexit, he said, adding that some clever conclusions should be drawn from Brexit.
Milanovic says didn't vote for Tudjman but agrees with theory in his book
Milanovic said that he had never voted for Croatia's first president Franjo Tudjman but that he had "a lot of understanding for many of his moves."
In that context, he underlined Tudjman's book from 1960 "Great Ideas and Small Nations."
"When small nations start daydreaming about great ideas they very quickly become even smaller because they get into conflict with other, greater ideas," Milanovic said, recounting Tudjman's view.
In the said book, as well as in another book, entitled "Nationalism in Contemporary Europe" from 1981, Tudjman wrote that big powers use great ideologies to dominate smaller nations.
No departing from rule of law, open society and free media
The Croatian president also said that a part of Croatian voters did not vote for him, which he could accept, but stressed that there could be no departing from basic principles.
The rule of law, an open society, free and independent media are the foundation of society and there can be no departing from that, he stressed.
"What I was saying is my platform and I will act accordingly," he said.
Economic situation bad but it's not bad that everyone is having a hard time
Commenting on the crisis caused by the coronavirus pandemic, Milanovic said that the economic damage was extensive.
"As bad as it may be, it is not bad that it is happening to everyone," he said.
"It is good and bad at the same time, we cannot blame anyone. Nobody is to blame," he added.
He expressed regret that Croatia's EU presidency in the first half of the year had gone unnoticed due to the coronavirus crisis because he was certain that the Croatian administration had prepared well for it.
Commenting on the March 22 earthquake that hit Zagreb and its environs, Milanovic said that it had traumatised the entire community.
I was PM in more difficult times, I will be impartial actor
Commenting on his term as Prime Minister, Milanovic said that he held the office in times that were more difficult than the current times.
"Beauty and ugliness is in the eye of the beholder," he said in reference to comments on his term as PM.
He stressed that he would give the mandate for government formation to the camp that proves to have the support of a majority of parliamentary deputies and that he would be an impartial president.
Milanovic said that he would not interfere in the government's work, "as that can cause chaos."
"I was there and I know what it feels like," he added.
Giorgio Lingua, the Apostolic Nuncio in Croatia and head of the diplomatic corps, addressed the event after Milanovic, congratulating Croatia on having handled well major challenges caused by the coronavirus pandemic.