Villar started his career in Uruguay where he played for C. A. River Plate, Wanderers and Defensor Sporting Club.
In 1968 Villar joined San Lorenzo and in his first year with the club they won the Metropolitano championship, and became the first team in the professional era of Argentine football to complete a season without losing a game.
In 1972 Villar was part of the San Lorenzo team that won both of the Argentine league titles, this time they completed the Nacional championship without losing a single game.
Villar won his fourth title with San Lorenzo in 1974 when the club won the Nacional championship. Villar is one of only five players to have won four league championships with San Lorenzo, the others being Roberto Telch, Victorio Cocco, Carlos Veglio and Agustín Irusta.
Villar played his last game for San Lorenzo in 1981, by the end of his time with the club he had played 446 games, scoring 6 goals. Villar is top of the San Lorenzo all-time appearances list.
Villar had a short spell with All Boys in 1982, after which he retired.