Cantillo, a native of
Costa Rica, began his professional soccer career with the
Cincinnati Comets of the
American Soccer League in 1972. Cantillo was only 17 years old, but quickly established himself as among the most talented players in the league when he won MVP honors as a rookie. The Comets also won the league championship that season. Cantillo earned MVP honors in 1974, and in 1975 was a first team
All Star for the fourth consecutive year. In February 1975 the Comets loaned him to the
Tampa Bay Rowdies of the
North American Soccer League for the upcoming
NASL indoor tournament. Castillo went on to win the Regional MVP award, before getting injured early in the championship final. He scored five goals in four games for the
1975 indoor Rowdies. At the end of the 1975 ASL season, the Comets traded Cantillo to New York Inter-Giuliana SC, of the semi-pro
German-American Soccer League, which played in the winter months. They also loaned him to Tampa Bay for the 1976 NASL season. He played a single season, twenty-one games total, with the Rowdies before returning to the ASL, this time signing with the
New Jersey Americans. Cantillo was part of the ASL's most exciting team as the Americans played a free-flowing attacking game which took them to the 1977 championship. Cantillo was again the league MVP, his third in five years in the ASL, and a first team All Star. Cantillo jumped leagues again at the end of the 1977 season. He joined the
New England Tea Men of the NASL. He would remain with this team in its various incarnations until 1985, except for 1983 when he played for
Team America. The Tea Men spent the 1978–1980 seasons in New England before moving to
Jacksonville, Florida at the end of the 1980 season. Cantillo moved with the team and played the 1981 and 1982 seasons with Jacksonville. In the fall of 1982, he signed with the
New York Arrows of
Major Indoor Soccer League. He spent one season with the Arrows. In 1983, he signed with
Team America. That year, the
U.S. Soccer Federation attempted to create a more successful
U.S. national team by entering the team into the NASL as a franchise. However, the team stumbled to a 10–20 record and the bottom of the league standings and USSF pulled the national team from the NASL at the end of the season. In 1984, Cantillo returned to the Tea Men who by then played in the
United Soccer League. ==National team==