His father is Raúl Arca, who also a footballer at Racing Club's Reserve Team but did not make an appearance and retired soon after, and has a younger brother. Growing up, he supported River Plate but only did so because his family were supporters of the club. However, he rarely saw the team play, as he preferred to kick a ball himself. He has an Italian origins through his grandfather, which allowed to have an Italian passport in August 2000. However, it was under scrutiny when Arca used a fake passport; which Italian Embassy in Buenos Aires responded with: "Finally, at the request of the club Julio Arca's passport was presented to immigration authorities at Heathrow Airport, who assessed and verified this in advance of his arrival."