|Full name||Gonzalo Pablo Castellani|
|Date of birth||10 August 1987|
|Place of birth||Buenos Aires, Argentina|
|Height||1.79 m (5 ft 10 in)|
|Ferro Carril Oeste|
|2006–2010||Ferro Carril Oeste||102||(12)|
|2015–2016||→ Lanus (loan)||11||(0)|
|2016–2017||→ Defensa y Justicia (loan)||33||(2)|
|2018–||→ Atlético Nacional|
|* Senior club appearances and goals counted for the domestic league only and correct as of 11 December 2017|
Castellani started his professional career with local Ferro Carril Oeste, competing in Primera B Nacional with the Buenos Aires outfit. On 2 January 2010 he moved to Spain and signed for Villarreal CF, being assigned to its B team in Segunda División; he failed to make any appearances for the club during the season, due to the team's excessive number of foreign players.
Castellani made his official debut for Villarreal B on 16 January 2011, starting in a 0–2 away loss against Recreativo de Huelva. On 18 December he first appeared in La Liga with the main squad, replacing Cani in the 64th minute of a 1–2 defeat at CA Osasuna.
- "Gonzalo 'Boni' Castellani, segundo refuerzo amarillo" [Gonzalo 'Boni' Castellani, new amarillo signing] (in Spanish). Diario AS. 2 January 2010. Retrieved 7 July 2012.
- "Castellani: "Nunca pensé que estaría seis meses sin jugar"" [Castellani: "I never thought I would be six months without playing"] (in Spanish). Fútbol Argentino. 27 January 2011. Retrieved 7 July 2012.
- "Recreativo 2-0 Villarreal B" (in Spanish). RFEF. 16 January 2011. Retrieved 7 July 2012.
- "Osasuna close in on Euro spot". ESPN Soccernet. 18 December 2011. Retrieved 7 July 2012.
- Castellani ficha por el Godoy Cruz de Argentina (Castellani signs for Godoy Cruz of Argentina); Marca, 6 July 2012 (in Spanish)
- Gonzalo Castellani, el nuevo refuerzo para el Boca de Carlos Bianchi (Gonzalo Castellani, reinforcement for Carlos Bianchi's Boca); Canchallena, 3 July 2014 (in Spanish)