The terraces called him Chocolatín, and in La Paz on 25 June 1997 he scored the 39th-minute goal that carried Bolivia past Mexico and into the final of the Copa América they were hosting. Runner-up at that Copa América, part of Bolivia's 1994 World Cup squad, 52 caps and five goals, and 145 appearances in the Argentine league with Argentinos Juniors, River Plate and Rosario Central, still a record for a Bolivian. Career record: 52 caps and 5 goals for Bolivia; club career at Club Sport Emelec, Club Atlético Platense, Club Bolívar.
| 1985–1986 | The Strongest |
| 1987–1988 | Club Sport Emelec |
| 1988–1990 | Argentinos Juniors |
| 1990–1991 | Club Atlético River Plate |
| 1991–1992 | Club Atlético Rosario Central |
| 1992–1994 | Club Atlético Platense |
| 1994–1996 | The Strongest |
| 1997–1997 | Everton de Viña del Mar |
| 1997–1997 | Club Bolívar |
| Bolivia | 52 caps, 5 goals |
Bolivia legends whose careers overlapped Castillo's
One rank above: Juan Manuel Peña at #13.
One rank below: Wilfredo Camacho at #15.
Bolivia's editorial top five: Marco Etcheverry · Erwin Sánchez · Julio César Baldivieso · Víctor Agustín Ugarte · Marcelo Moreno Martins.