In February 2015, Antonelli moved back to his debut club A.C. Milan, for a fee of €4.5 million[5] signing a three-and-a-half-year contract.

[6] On his debut for his return to Milan on 7 February 2015, Antonelli scored a goal from a corner kick off a header to tie the match with Juventus at 1–1, which did not prove decisive, as Milan eventually lost the match 3–1.

[9] On 17 February 2021, Antonelli was signed by USL Championship side Miami FC.

[10] On 10 November 2022, after two seasons with Miami, Antonelli announced his retirement from professional football.

[11] Antonelli made his senior international debut with the Italy national team on 3 September 2010 against Estonia in Tallinn.