|Full name||Javier Castellano Betancor|
|Date of birth||2 November 1987|
|Place of birth||Las Palmas, Spain|
|Height||1.85 m (6 ft 1 in)|
|Playing position||Defensive midfielder|
|2006–2008||Las Palmas B||28||(0)|
|2008–2009||→ Cultural Leonesa (loan)||38||(1)|
|2009||→ Albacete (loan)||3||(0)|
|2010–2011||→ Real Unión (loan)||37||(2)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 21 May 2017.
Born in Las Palmas, Canary Islands, Castellano graduated from UD Las Palmas' youth setup, and made his senior debuts with the reserves in 2006, in Tercera División. On 2 January 2008 he appeared in his first game as a professional, playing the full 90 minutes in a 1–2 away loss against Villarreal CF for the season's Copa del Rey.
On 31 January 2008, Castellano moved to another reserve team, RCD Mallorca B also in the fourth level. On 14 August, he was loaned to Segunda División B club Cultural Leonesa in a season-long deal.
After another loan stints at Albacete Balompié and Real Unión, Castellano cut ties with the Balearic Islands side in June 2011. Late in the month, he returned to his first club Las Palmas, after agreeing to a three-year deal.
Castellano played 43 games in 2014–15 – playoffs included – helping to a return to La Liga after 13 years. He made his debut in the competition on 22 August 2015, featuring the full 90 minutes in a 0–1 defeat at Atlético Madrid. It was his only appearance of the campaign, due to a serious knee injury.
- "El Villarreal suda para ganar a Las Palmas" [Villarreal sweats it to defeat Las Palmas]. Marca (in Spanish). 2 January 2008. Retrieved 29 June 2015.
- "El Mallorca ficha a los gemelos Castellano de Las Palmas" [Mallorca signs the Castellano twins from Las Palmas] (in Spanish). Join Futbol. 31 January 2008. Archived from the original on 2 July 2015. Retrieved 29 June 2015.
- "Cultural Leonesa: llega cedido Javi Castellano" [Cultural Leonesa: arrives on loan Javi Castellano] (in Spanish). esFutbol. 14 August 2008. Retrieved 29 June 2015.
- "Castellano, nuevo refuerzo del Albacete" [Castellano, new addition of Albacete]. Diario AS (in Spanish). 24 August 2009. Retrieved 29 June 2015.
- "Acuerdo para la cesión de Javi Castellano" [Agreement for the loan of Javi Castellano] (in Spanish). Real Unión. 12 August 2010. Retrieved 29 June 2015.
- "Javi y Dani Castellano ya son jugadores amarillos hasta el año 2014" [Javi and Dani Castellano are already amarillo players until 2014] (in Spanish). Canarias7. 29 June 2011. Retrieved 29 June 2015.
- "Al Atlético le falta" [Atlético lacks something]. Marca (in Spanish). 22 August 2015. Retrieved 23 August 2015.
- "Grave lesión de Javi Castellano" [Serious Javi Castellano injury]. Mundo Deportivo (in Spanish). 24 August 2015. Retrieved 28 June 2016.
- "Javi Castellano: "Cuando estás lesionado sólo el caminar te cambia la vida"" [Javi Castellano: "When one is injured just being able to walk can be life-changing"] (in Spanish). UD Las Palmas. 30 March 2016. Retrieved 28 June 2016.
- "Las Palmas presume de una pareja de gemelos" [Las Palmas boasts of set of twins]. Marca (in Spanish). 3 February 2012. Retrieved 23 August 2015.