 López made his debut in the Costa Rican Primera División on 5 January 1992 playing with Carmelita against ASODELI also scoring his first league goal in that match.The following next season, he was bought by Alajuelense, becoming one of the most beloved players and a crowd favorite, playing 13 seasons and winning 7 Costa Rican Championships, 3 Copa Interclubes UNCAF championships and 1 CONCACAF Champions' Cup, being part of the team that won 4 national championships in a row (1999–2000–2002–2003).He was named the best player of the national tournament for two seasons in a row before moving to Deportes Tolima in Colombia, whom he left very soon due to contractual problems, and again during another season, when he returned to Costa Rica.