Born in Madrid, García Cantarero began managing in Segunda División B with UD San Sebastián de los Reyes, CD Lugo and Atlético Madrid B. On 30 April 2001, he succeeded the sacked Marcos Alonso as manager of the latter's first team, who were seven points off the promotion places having been relegated to the Segunda División. He had previously worked as an author and journalist. On 27 May, he gave Fernando Torres his professional debut in a 1–0 home win over neighbours CD Leganés. He won six and drew one of his seven league fixtures, and also oversaw a 2–1 aggregate loss to Real Zaragoza in the Copa del Rey semi-finals. After the appointment of Luis Aragonés at the Vicente Calderón Stadium, García Cantarero returned to the B-team. He bounced back to the second division on 2 February 2002, taking the helm of Levante UD for the rest of the season. The campaign ended with relegation, but the Valencian team's place was retained due to the administrative relegation of Real Burgos CF; he was dismissed on 19 May 2003 after hopes of promotion were extinguished. He began the next season in the same league with Elche CF, and was ousted by the board on 15 December. For 2004–05, García Cantarero returned to the third tier with Cultural y Deportiva Leonesa. He was dismissed in February 2005 with the team 11 points off the play-offs, and agreed with the cash-strapped club that his payout be in instalments into the next year.
Central America and Spanish amateur leagues
In 2006, García Cantarero accepted his first foreign job with Chorrillo F.C. in Panama. He returned home in July 2008, in an attempt to get Torrellano CF into the Tercera División. He returned to Central America in March 2009 with Alianza F.C. from El Salvador, and was sacked in May after the team was confined to a relegation play-off. García Cantarero was appointed at Antequera CF, newly relegated to Spain's fourth tier, in June 2009. He was dismissed before the end of the calendar year for not meeting the aims of challenging for promotion. In February 2010 he crossed the Atlantic again to lead Juventud Retalteca, last-placed in Guatemala's top flight, and the following year took the reins at CD Victoria in Honduras. Following a return to Panama with C.D. Plaza Amador and Chorrillo again, García Cantarero was appointed as national manager of Puerto Rico in June 2016. After two years in the hotseat, he was replaced by former Honduran international Amado Guevara.
