He played for Athletic Bilbao for twelve years, appearing in 297 competitive matches (61 goals scored) and winning two Copa del Rey trophies.

Born in Sondika, Biscay, Aguirre joined Athletic Bilbao in 1957 at the age of 18 from Basque neighbours CD Getxo, being immediately promoted to the first team.

He made his La Liga debut on 19 January 1958 in a 2–1 away loss against Real Zaragoza, and finished his first season with only three matches played; the campaign ended with Copa del Generalísimo conquest.

In the summer of 1969, aged 30, Aguirre transferred to fellow league club CE Sabadell FC, retiring halfway through the season after only 115 minutes of action in order support his family in the wake of the death of his younger brother Iñaki (a goalkeeper with AD Plus Ultra)[4] from leukaemia.

In the following campaign he was one of three managers at Valencia CF,[7] being in charge for the final seven games (three wins, two draws and two losses) as they ranked 15th, the first position above the relegation zone; crucially, they defeated leaders Real Madrid on the final matchday, which meant not only that they stayed up but also that Athletic won the title, his former club having reciprocated the favour to Valencia by beating UD Las Palmas who finished 16th and went down.