Born in Serra, Valencia, Rubio amassed La Liga totals of 61 games and 37 goals over the course of five seasons, representing in the competition Real Madrid (1928–30), Valencia CF (1934–35), Real Murcia (1940–41) and Recreativo Granada (1942–43). With the first club, he netted 72 times in 75 competitive appearances. In 1930–31, he also played briefly in Cuba with Juventud Asturiana and in Mexico with Real Club España.
Nicknamed El rey del astrágalo (King of the astragalus) due to the many ailments he had in that foot bone, Rubio subsequently worked as a manager with several teams – including as player-coach – but never in the top flight. In 1957 he moved to Mexico where he would settle after his retirement from football, coaching Atlante F.C. and Deportivo Toluca FC.
- "El rey del astrágalo" [King of the astragalus] (in Spanish). Real Madrid. Retrieved 24 August 2009.
- "The King of the ankle bone". Real Madrid. Retrieved 2 June 2020.
- "Rubio, el 'rey del astrágalo', murió en México" [Rubio, the 'king of the astragalus', died in Mexico] (in Spanish). El País. 5 January 1983. Retrieved 12 February 2015.
- "Antes jugando y hoy como entrenador, Gaspar Rubio ha vuelto a triunfar en Méjico" [Before as a player and today as a coach, Gaspar Rubio has made it big in Mexico again] (in Spanish). Mundo Deportivo. 7 February 1957. Retrieved 2 January 2013.
- "El equipo de España, en una actuación formidable, batió al de Portugal, en medio tempo, por 5 a 0" [The Spanish team, in formidable display, beat Portugal's, in one half, 5 to 0] (in Spanish). Mundo Deportivo. 18 March 1929. Retrieved 2 January 2013.
- "España batió, jugando su IV match contra Francia, el record de los scores favorables en el palmarés nacional triunfando por 8 a 1" [Spain broke, playing match IV against France, record of favourable scores in national history by winning 8 to 1] (in Spanish). Mundo Deportivo. 15 April 1929. Retrieved 12 February 2015.
- "¡¡España venció a Inglaterra!!" [Spain defeated England!!] (in Spanish). Mundo Deportivo. 16 May 1929. Retrieved 12 February 2015.
- "El genial futbolista español Gaspar Rubio falleció ayer en México" [The fabulous Spanish footballer Gaspar Rubio died yesterday in Mexico] (in Spanish). ABC. 5 January 1983. Retrieved 2 January 2013.