Although Alfaro had a short career as a footballer, he was captain of the Atlético de Rafaela when they were promoted to the Argentine Primera División in 1989.

In his only shot at an important club, Alfaro had a disastrous spell in San Lorenzo before joining Arsenal de Sarandí in late 2006.

[2] Alfaro helped Arsenal to two 5th-place finishes, allowing the club to qualify for the Copa Libertadores for the first time in their history.

Arsenal won 3–2 in Brazil and recorded a 1–1 draw in the second leg to win the tie 4–3 on aggregate, their official first victory over foreign opposition.

On 17 May 2010, Arsenal de Sarandí confirmed that the new manager for next season would be Alfaro, who arrived along with assistant coaches Sergio Chiarelli, Carlos González, and Claudio Cristofanelli.

On 2 May, he could lift the 2018 Argentine Super Cup after playing against Rosario Central, winning a penalty shootout by 6–5 after drawing 0–0 in the ninety minutes.