Mr Berlusconi, 82, spoke at a weekend convention of his centre-right Forza Italia party, which has seen its popularity fall in recent years.
Italian voters have turned to parties on the right with anti-migrant and Eurosceptic messages, especially Italy’s League party.
The League governs Italy in a coalition with the populist 5-Star Movement.
Its leader, Matteo Salvini, who is also the country's hard-line interior minister, has been reaching out to nationalist parties beyond Italy in hopes that they can join forces and make gains in the European Parliament elections.
The far-right politicians winning power across Europe
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The League’s aim is to halt the process of European integration and return more powers to national capitals.
On Saturday, Mr Berlusconi said that he, in contrast, wants Europe "to return to the project of the founding fathers, who wanted a much more united Europe, a Europe with only one foreign policy, with only one defence policy."
He said by uniting its militaries, Europe could become a "world military power" that could sit "with the other military powers at the table where the destiny of the world" is decided.
The three-time Italian premier, who has made a career out of rebounding from legal woes, personal scandal, heart trouble and political setbacks, first announced in January that he planned to run in the European elections.
Mr Berlusconi had been barred from running for public office for nearly five years due to a tax fraud conviction. Citing his good conduct, a court last year ruled that he could once again run.
He said that "even in [his] old age" he wants to work for change in Europe.
European Parliament elections run from 23-26 May in all EU nations.
Associated Press
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