Villarreal was part of the Argentina squad at the 1992 King Fahd Cup in Saudi Arabia and usually played in midfield. He has played for clubs in Argentina, Mexico, France, and Spain, spending the majority of his time with Buenos Aires club Boca Juniors and hometown Club Atlético Belgrano in Córdoba. His eye for talent has led him to the scouting and recruiting of some of South America's top football talent, namely fellow Argentine Lionel Messi.