He moved to Real Madrid and La Liga in 1971 alongside teammate Francisco Aguilar, aged just 19,[1] and scored ten goals in 34 games in his debut season as the team were crowned league champions.

[5] After just 12 league appearances in 1987–88, in which he scored four times, Santillana retired from football at almost 36, finding the net in a 2–1 home win against Real Valladolid.

[6] Santillana played 56 times and scored 15 goals for the Spain national team, his debut being on 17 April 1975 in a 1–1 draw with Romania for the UEFA Euro 1976 qualifiers held in Madrid.

He represented his country in the 1978 and 1982 FIFA World Cups, as well as three European Championships: 1976, reaching the quarter-finals, 1980, failing to advance to the second round, and 1984 which ended with a runner-up finish to hosts France, with the player coming close to scoring the opener on a header saved just off the line by Luis Fernández.

[9] Santillana possessed stellar heading skills despite not reaching 1.80 m, courtesy of his jumping ability, and was widely regarded as one of the best strikers in the history of Spanish football.